The Poetics of Music in the Form of Six Lessons by
Igor Stravinsky
A series of lectures that Stravinsky presented to Harvard. There's a great deal of insight as is to be expected, but it's also weirdly authoritarian and reminds me a lot of the "dancing about architecture" trope whenever he digs into aesthetics specifically. The language, flow, and style of it is rough too, but I'll let the translator take the blame for that. Valuable for musicians and Stravinsky heads.