This fascinating book presents a detailed account of Messiaen's compositional techniques and development up through the early 1980s (he died in 1992). Johnson writes very clearly and uses a lot of examples and diagrams to explain what is going on in the music, so despite the fact that this book is very technical, it never became too dense or hard to follow. Johnson covers all the main works up through 1983, with an especially interesting chapter on Catalogue d'Oiseaux. This book gave me a fresher and deeper understanding of what Messiaen did in his music, why he did it, and how it all works. I love Messiaen's music, so I very much enjoyed reading this book. It has made me want to go back an listen to all the pieces covered to see how my new understanding of what is going on in them will change my experience of them.