 The examination of perception that Śāntarakṣita and Kamalaśīla undertake in the Compendium and its Commentary draws from a centuries long and rich history of philosophical debate. This chapter reviews some of the most important aspects of this debate, while at the same time providing a thorough examination of the overall scope and content of their works. It argues for the need to view the encyclopaedic pursuits of Śāntarakṣita and Kamalaśīla both in doxographical terms, and as an effort aimed at establishing the core Buddhist metaphysical principles on a sound epistemological foundation. Finally, by mapping the ontological and epistemological domains of Buddhist and Indian philosophy, the chapter also invokes the principle of clarity and a version of Okham's razor to defend the parsimonious epistemology of the Buddhists.