Olivier Messiaen's 'Technique de mon langage musical' was originally published in 1944, in two volumes (textbook plus musical examples), and revised in 1956. Both editions were published by Leduc in Paris, France.
Here's the english translation of the textbook, published in 1990 as 'The technique of my musical language', plus the french edition of the 'Examples musicaux' (musical examples), both in pdf.

Packed as a contiguous zip inside a single 7z.
Served by RS, redirected through lix.in.
Messiaen - Technique.