Published ten years ago, I have found Descartes' Meditations: Background Source Materials very useful when attempting to make more sense of the intellectual context in works of not just Descartes but Spinoza and other major early modern philosophers as well. Translators of this collection of primary sources are Roger Ariew (South Florida), John Cottingham (Reading), and Tom Sorell (Birmingham). Marjorie Grene (Virginia Tech) co-translated one of the selections as well.
Primary Sources Online
- Constitution Society
Ethica, TTP (Jonathan Bennett's translations).
- Project Gutenberg
Ethica (Dutch). TIE, TTP, Ethica (English).
- Rudolf W. Meijer Site
TIE, Ethica, TP, Ep (Latin).
- Spinoza / BDSweb
Various primary sources in Dutch, English, French, German, Latin, and Russian.
- Spinoza et Nous - Philosophie de l'affirmation - Oeuvres
TIE, TTP, Ethica (French).
- The Spinoza Study
KV, TIE, CM, TTP, Ethica (in split-frame mode).