'An elegant enigma' takes the story of the Voynich Manuscript right up to the time of the book's publication (1976).
D'Imperio's approach to the enigma in her title is free of nonsense and constructive: she suggests avenues of research for the interested reader and rightly dismisses theories that are now untenable (for example, that Roger Bacon was the author of Beinecke 408).
With its useful appendices, pragmatic approach, and logical organization , this gem of a book (free to download from the Internet Archive!) might well be the best introduction to the Voynich Manuscript out there.