This is an older book but has a lot of great information on why memory works and practical exercises. A lot of tips on spotting methodologies that are trendy instead of science based. The main take away I liked was: Interest, Attention, and Exercise. This combined with a daily reflection to solidify memories in your mind were great insights and not gimmicky. If you want to improve your memory, you owe it to yourself to read this and get some terrific information.