kaberett | free academic books (Reply)

Springer Verlag academic text(book)s (via sebenikela): wide variety of topics, where I've grabbed a mix of chemistry and sociology and psychology and programming and physics
Project Muse (ditto): a frankly... overwhelming... number of academic presses (with a landing page that makes it clear when the texts will be available for download until)
An Introduction to the Rock-Forming Minerals, or -- as we collectively refer to it -- "DHZ" (via my supervisor): this has pretty much everything you could ever need or want to know about the structure and properties and identification of, well, the rock-forming minerals