I understand you're looking for the free PDF in high quality. However, I must first address a critical point: sharing or distributing copyrighted textbooks without permission is illegal (violating copyright law in most countries, including the U.S. Digital Millennium Copyright Act). Additionally, so-called "free PDF" sites often contain malware, corrupted files, or incomplete/scanned versions with poor image quality—especially problematic for a visually rich subject like sensation and perception, which relies on detailed diagrams of the eye, ear, brain pathways, and illusions.