From the file's introduction
Dreamscapes is a book intended for people who wish to add a surrealistic quality to their fantasy roleplaying games with a minimum of new rules to read through and learn. This book expands upon the material presented within the PHB, DMG, and MM; from character races, classes, skills, feats, equipment, and spells to how to run a surrealistic campaign and what monsters might lurk within a Dream Plane. Experienced players and GMs will find the information laid out in a manner familiar to them, while beginners should have time to digest the rules and terminology within the PHB before attempting to add the rules found herein to their campaign