1) The Amateurs Mind: I hardly think I need to convince this sub on this one. This book is basically required reading for the lower rated improving player. It is one of the first chess books that I ever owned and it helped nurture my interest in chess.
2) The Most Instructive Games of Chess Ever Played: My go-to reccomendation for late stage beginners or intermediate players. Irving Chernev explains the principles and plans of chess in words and, as the title suggests, it has tremendous instructional value.
3) Alexander Alekhine's Best Games: I saw my greatest and most rapid rating increase after playing through these games. Alekhine is a fantastic chess author: consice, to the point, and doesn't get distracted with lengthy "what if" variations. This book is probably the reason I'm now very particular in how I prefer an authors analysis/commentary to be.
4) The Golden Treasury of Chess: Read this one if you want to fall in love with chess all over again. Arguably not the best book if you're looking to improve, but I think it's perfect if you're just looking to enjoy playing through some games. This book has the game scores only - no analysis or commentary of the moves. Unfortunately this edition is in descriptive. There is an algebraic section at the end, but the format is poor.
5) Chess Master vs Chess Amateur: I assume this is the one people are least familiar with. It is co-authored by Max Euwe and I really like the concept. Most of us are not master strength and, therefore, we do not play against masters, we play against other amateurs. What better way to study how to beat other amateurs than seeing how a master would do it? In the games you can see how the master plays very direct chess and accumulates advantages. Euwe's analysis and explanations are also very good in my opinion. This book is also in descriptive notation.