Paul Griffith's overview of Boulez's music, an entry in the Oxford Studies of Composers series, covers the great French composer's work up to 1978. Though only 60 pages on, it packs in a lot of musicological analysis and lots of cool quotations from scores.
The book is divided into five chapters, covering Boulez's early work, the era of total serialization, "Le Marteau sans maitre", his chance works, and finally "works in progress." I found the fourth chapter (titled "Alea") the most eye-expanding, as it elucidates the serial writing of "Constellation"/"Constellation-Miroir" and "Pli selon pli". The works then in progress discussed in the last chapter include "Messagequisse", "Rituel", "...explosante-fixe...", and "Eclat"/"Eclat-Multiples".
It's a pity that the book has not been updated to cover Boulez's big comeback in the late 1980s, when "Repons" was completed and "...explosante-fixe..." dramatically reworked. The book's age shows in its discounting of "Notations"; the author could hardly be aware that Boulez would return to this early music to orchestrate it. Still, the work is useful for those interested in Boulez's early music. Also check out Jarmeux's biography-cum-analysis published by Oxford in 1991.