Grammaire du Solresol (book)

The second major book about Solresol, written by the other major contributor to Solresol, Boleslas Gajewski.

While originally written in French, translations can be found online in English, Spanish, German, Portuguese, and Russian.

Translation
Should be rendered into wikitext, but here it is for now:

http://c.sidosi.org/resources/grammar-of-solresol/grammar-of-solresol.html