The discussion centers around recommendations for problem books similar to the LIM series, focusing on quantum mechanics, statistical mechanics, and atomic physics. Participants suggest utilizing Amazon's search function for more options. Specific titles mentioned include works by Krotov, Irodov, Saraeva, and Kosel, each known for their problem-solving approach. Additionally, "A Guide to Physics Problems" is highlighted as a valuable resource. The difficulty and types of problems in these books vary, catering to different levels of expertise.