Books like Principia philosophiae by René Descartes

Descartes' 1637 classic, "Discours de la méthode," introduces systematic doubt, clear reasoning, and methodological principles that underpin modern philosophy and the science of knowledge.

A concise exploration of Bertrand Russell’s key philosophical questions, focusing primarily on epistemology while briefly addressing metaphysics and other contemporary issues.

Review: 'This new translation is designed as a replacement for the old but still widely used translation by Elizabeth Haldane and G. R. T. Ross ... Unlike the Haldane and Ross edition which was translated from a composite text based on both the French and Latin editions, the present translation is made from the Latin text alone, with significant changes in the French edition indicated in the footnotes. This is clearly much more satisfactory. The translation is generally accurate, and is neither excessively free nor excessively literal ... There is little doubt that this will become the standard translation of Descartes' philosophical writings, and it deserves a warm welcome.' French Studies Basics: Based on the new two volume Cambridge edition of the Philosophical Writings, this anthology of essential texts contains the most important and widely studied of the writings.

David J. Chalmers explores the mystery of consciousness, arguing that a reductive, purely materialist account is insufficient and outlining a possible fundamental theory linking physical processes and subjective experience.