The book provides a general introduction to memory and sleep, focusing on computational understanding. It includes various fundamental and advanced topics related to learning in biological and computational systems, neurotechnology, NeuroAI, and neuroethics.The book systematically covers major memory categories, neural substrates of memory, brainwaves and their relationship to memory, sleep's role in memory, dreaming, memory consolidation.The book includes important historical accounts and anecdotes of scientific discoveries. It includes 58 illustrations, hundreds of notes and references. The book bridges the gap between memory and computation, provides novel computational perspectives of brain disorders and mental illnesses. It includes discussions on many computational models such as the attractor network, predictive coding, Bayesian inference, and reinforcement learning.The book provides documented clinical observations of memory-related diseases (such as amnesia) and the stories of patients.The book provides outlook on stem cells, organoids, memory manipulation, closed-loop neural interfaces, cutting-edge AI, neurotechnology, and their roles in future memory research.