1.  …  “Written” is a hangover from the  earlier period when the work was believed an autograph, and thus written at the time it was made, more or less.  To conflate composition of the text(s) with manufacture of the object is a basic error, avoidance of which is drummed into the novice in ‘manuscript studies 101’.  ‘Made’ or ‘compiled’ would be appropriate.
2. … during the late fifteenth or early sixteenth centuries.  The Beinecke library must have some reason other than credulity, reliance on amateur preferences, or deference to past members of staff to justify its including this apparent error. If so, I haven’t seen that explanation  The radiocarbon dating of 1404-1438,  which agrees with Panofsky’s opinion in 1932, and with the ‘expert consensus’ of which Lehmann-Haupt spoke in 1963,  would all seem to demand that to add a century to that range should not be done arbitrarily but from the basis of concrete information – from codicology or materials science. (Lehmann-Haupt’s comment is reported by d’Imperio, Elegant Enigma (1978) p.8
   *’central Europe‘. The phrase is uselessly vague and there has been no technical or historical study which proved the manuscript to have been “written in central Europe”.  The ‘central Europe’ theory was always an anchronism, and was initially focused on the German-speaking centre of Europe and on Rudolf’s court.  When the radiocarbon dating established the work as early fifteenth century, there was not a man of the ‘central European’ theorists left standing.  (As a matter of interest, those who were left standing were Patrick Lockerby, Nick Pelling, Philip Neal, and the present writer’.
   Some of the most dedicated ‘central European’ theorists  tried at first to ignore the radiocarbon dating; then to say that ‘1404-1438’ could be redefined as 1470 and later. Ideas that ‘the manuscript was made in about 1480’… nearly became another ‘canonised myth’. The latest tactic has been to re-define ‘central Europe’ to include England, northern France and northern Italy… which makes the whole ‘central Europe’ tag meaningless.
3. … magical or scientific text – experts in those texts and subjects have either denied any link exists between the Voynich manuscript and European works of that kind, or have failed to produce any comparison from the Latin corpus to justify the idea.   It is speculation, and nothing more.
4. …113 plant species.  ‘113 pictures’ would be accurate.  To assume that each image is a ‘portrait’ of a single species is another canonised myth, unproven and contraindicated by the fact that the Voynich plant pictures are matched neither in  form nor in sequence by the imagery in medieval herbals.  Many spurious ‘pairings’ have been offered over the years, but none can bear analytical examination.
5. * astronomical and astrological drawings.  The sense in which this phrase is meant presumes, again, that some place exists for these drawings in the Latin European corpus or in ‘acceptable’ introductions to that corpus from the Islamic astronomical works. The basic forms, and elements in Latin astrological works are absent from the Voynich manuscript, or if present are not yet demonstrated present. The angular horoscope drawings, and reference to the planets are among the most obvious discrepancies. If they are astronomical, the specific type of ‘astronomical’ writing in general needs to be identified, especially given that the ‘zodiac’  contained in the Voynich calendar does not depict the 12 constellations or even ten of the twelve.  It includes 2 ‘bulls’ and 2 ‘goats’ but no sheep drawn in the usual Latin manner with over-curled horns.  It is however true that in parts of France (the same where the standing archer first appears as ‘Saggitario’) one finds occasional depiction of Aries as a goat.  More on this later.
6. … biological section.  This description is no more than the subjective impression expressed by William Romaine Newbold.  Others, just as arbitrarily, describe the same drawings as ‘balneological’.
7. … nudes.  The term is pre-emptive.   The term ‘nude’ describes a drawing from life, meant to represent a living figure.  At present, there is as great a probability that the figures were intended to be metaphorical or allegorical as literal, and the more neutral term ‘unclothed’ or ‘naked’ is appropriate here.  The figures are shown partly covered (or not) but to say ‘they wade’ is to assume greater literalism than is justified by the evidence.
8. …. an elaborate array of nine cosmological medallions.  Once again, the description fails to maintain the neutral tone appropriate to description of images whose content is – or is believed – unknown.  Whether or not the Beinecke librarians have time to keep abreast of current writings, there is nothing to explain or to justify use of the word ‘cosmological;’.  Others may speculate and argue over the intention behind the drawing, but the Beinecke’s information is expected to have a solid basis in fact.
9. … pharmaceutical drawings.  Speculation which has all but achieved the status of ‘canonised myth’ despite its being apparently denied by the form of the more ornate containers and the failure of any researcher to discover a ‘phamaceutical’ text having this form within the Latin (western European) corpus.
10. …. *medical – another widespread assumption, arrived at by analogy with, and assumption of, European models, and still without proof that the analogy is apt.

Scientific or magical text in an unidentified language, in cipher, apparently based on Roman minuscule characters; the text is believed by some scholars to be the work of Roger Bacon since the themes of the illustrations seem to represent topics known to have interested Bacon …  A history of the numerous attempts to decipher the manuscript can be found in a volume edited by R. S. Brumbaugh, The Most Mysterious Manuscript: The Voynich “Roger Bacon” Cipher Manuscript (Carbondale, Illinois, 1978). Although several scholars have claimed decipherments of the manuscript, for the most part the text remains an unsolved puzzle. R. S. Brumbaugh has, however, suggested a decipherment that establishes readings for the star names and plant labels; see his “Botany and the Voynich ‘Roger Bacon’ Manuscript Once More,” Speculum 49 (1974) pp. 546-48; “The Solution of the Voynich ‘Roger Bacon’ Cipher,” [Yale Library] Gazette 49 (1975) pp. 347-55; “The Voynich ‘Roger Bacon’ Cipher Manuscript: Deciphered Maps of Stars,” Journal of the Warburg and Courtauld Institutes 39 (1976) pp. 139-50.

Brumbaugh concludes that the manuscript is a sixteenth-century product, probably put together by the Englishman John Dee rather than the thirteenth-century Roger Bacon. He divides the manuscript into five parts and says that possibly two sections go back to the thirteenth century but that the other three and this compilation definitely date from the sixteenth century.

He also identifies the alphabet used in the cipher; with this alphabet he read the planet [sic.] and star labels. Brumbaugh concludes that the cipher originated in some type of numerology and that it is probably some type of artificial language. Thus the reader knows where work on the manuscript and its cipher stands today, the areas and avenues future research will follow, and what the manuscript will probably reveal if and when all parts of it are completely deciphered. Brumbaugh’s compilation places the Voynich Cipher Manuscript in its proper historical context ,,
Gregory S. Guzman (Bradley University),  The Historian, Vol. 42, No. 1 (Nov. 1979), pp. 120-121.

d’Imperio was polite but concluded:

“There is just enough plausibility in [Brumbaugh’s] process to lead one on. but not enough to leave one satisfied.” (D’Imperio 1978 p38)

Vera Filby said the same:

 Brumbaugh’s solution, though presented in a most interesting way, is disappointing, since the evidence he offers is incomplete, and proof -unambiguously readable text- is lacking.

It is unfortunate that he did not have the benefit of recent analyses of the script by Captain Prescott Currier and Mary E. D’Imperio, described in Manuscripts, Winter 1978. For readers unacquainted with the history of the manuscript and its remarkable provenance-from the first known reference to it in 16th-century [read ’17thC] Bohemia, to its rediscovery in 1912 in Italy by the rare-book dealer Wilfrid M. Voynich, and finally to the Beinecke this attractive book, with illustrations of representative manuscript pages, provides a thorough, even somewhat repetitious, overview. …

Vera Ruth Filby, (Department of Defence, in Washington).  Her review was published in  American Scientist, Vol. 67, No. 2 (March-April 1979), p. 249.

Filby’s opinion remains the general one, Brumbaugh’s claimed decryption method having been generally rejected.

Brumbaugh similarly converted Voynichese to digits …and tried to salvage text from the resulting digit stream, though ultimately accepting somewhat grudgingly that the digit stream was not meaningful.  Claude Martin travelled much the same path as Brumbaugh, proposing instead that it was constructed from a deliberately nonsensical digit stream. In my opinion, both Brumbaugh’s and Martin’s digit stream theories explained nothing whatsoever about the nature and structure of Voynichese, and so have nothing to commend them: and σαν ετι I don’t see any reason why I should think differently about Grosse’s superverbose digit stream theory. Sorry to have to point it out, but “it’s like that, that’s the way it is”.

Nick Pelling, ‘First Voynich Theory of 2012…’ (Jan. 28th., 2012)

Professor Bax went into detail on Brumbaugh’s claims of decipherment  (October 19th., 2014).

In the 1970’s (in fact before D’Imperio’s monograph) Brumbaugh produced a series of claims that he had ‘cracked the code’, among them an article on the VM star names which he claimed he had deciphered . In that article he boldly states: “In 1972 I finally solved the Voynich cipher” (Brumbaugh 1976:140).

Before addressing his decipherments themselves, it is interesting to reproduce a few of Brumbaugh’s observations concerning what he terms the ‘star names’, to give a flavour of his work:

“The star-map section raises problems. The star maps are a set of twelve, representing ten signs of the zodiac; originally there must have been at least one for each sign of the zodiac, but if so, two have been lost. Each ‘map’ has a central medallion with a picture of the zodiacal constellation, with the month name written beneath in plain text. Around this, in an inner circle, the maps have a ring of female figures, each attached by a line to a star. An outer circle has more such figures. A group of numerals is written next to each star.” (Brumbaugh 1976:141)

On the next page he [Brumbaugh] continues as follows:

“A group of cipher numerals is written next to each star. A first try at decipherment gave the name of Alfred for the star in the Pisces medallion, with Urifydes just above and Alfansus Purus on to the right. The names are therefore those of the great men whose souls are attached to stars, rather than anything else they might be—Arabic star names, or a numerical Messier listing, for example.” (Brumbaugh 1976:142)

Brumbaugh does not give details about his decipherment, and it is even not clear from this which precise words he was deciphering (e.g. in the Pisces ‘medallion’). Unfortunately, partly because of this sort of vagueness, his resulting decipherment did not find favour with other scholars…and his scheme of decipherment is now largely forgotten.

In terms of his analysis of the star names, I would further argue that he made a number of fundamental assumptions which are questionable, even untenable. In the quotations above, for example, he assumes that what we now call the Zodiac pages are in fact ‘star maps’. This involves the assumption that the drawings of star-shaped objects attached to lines or strings are necessarily meant to represent stars, as he says on pages 140 and 141, although by page 142 he has revised this to suggest they represent not stars themselves but ‘great men whose souls are attached to stars‘.

This raises a crucial question which to my mind (and again to my surprise) has not been carefully addressed in Voynich scholarship so far, neither by D’Imperio, nor by Brumbaugh, nor apparently by anyone else, namely which star-like drawings with labels in the manuscript should we take with confidence to represent stars, and which should we exclude from our analysis …

Stephen Bax, ‘Voynich star names: an analysis (1)‘, (October 18th., 2014)

Reviews of the Goldstones’ book, The Friar and the Cipher see it is an interesting history of Roger Bacon’s time, but include comments such that below ..

Ostensibly the book is about the Voynich Manuscript,….[but] this debate begins on page 223 of the edition I have. The book runs just over 300 pages, which presents kind of a problem. The rest of the book is a history of Western thought and the constant struggle between science and religion in the Middle Ages, Which brings me to the ultimate problem with this book and how it was marketed (and even titled). The Friar and the Cipher is a wonderful book on Western philosophy. However, there is nothing really new in the book when it comes to the manuscript. It takes no sides in the controversy, only saying that it seems likely that Bacon did write it. The authors raise questions but do not really provide anything new to readers with any knowledge of the subject. The book seems to be a way to gather a bunch of different sources into one volume, sort of a “this is where we’re at” kind of thing. It also is almost a love letter to Roger Bacon…

from Dave Roy, ‘Curled up’ reviews (2006),