Given the wide variety of poker books written over time, it may be surprising to learn that very few have been written on Pot-Limit Omaha (or any flavor of Omaha at all!). The books below offer a solid foundation for beginners and more advanced players alike.
Pot-Limit Omaha Poker by Jeff Hwang (2008). This book is a classic and a must-read for PLO learners. If you have never read a book on PLO, this one is a good place to start. It is clear and easy to read, even for the novice player. Hwang shares numerous examples and offers hand quizzes to help you solidify your learning. The strategic approach Hwang advocates is on the tight side, but that is not a bad thing given the potential wildness of this game.
Mastering Pot-Limit Omaha: The Modern, Aggressive Approach by Okolowitz and Taschner (2014). This book teaches an aggressive style of PLO play. There is a heavy focus on board textures and pre-flop hand selection. This is one of the best books out there for intermediate to advanced PLO players.
Omaha Poker by Bob Ciaffone (2006). Originally written in the 1980’s, this is a classic foundational Omaha book. While a bit dated, this book still stands as one of the must-reads for Omaha beginners. It covers not only Omaha basic play and strategy, but also talks about the history of the game.
Secrets of Professional Pot-Limit Omaha: How to Win Big, Both Live and Online by Rolf Slotboom (2006). This is an older book, appropriate for more advanced players. The focus is on short-stack play, which is a lower-risk approach to this often volatile game.
Advanced Pot-Limit Omaha (3 Volume Series) by Jeff Hwang (Various). Once you have mastered the basics, Hwang will take you through a variety of approaches in these three volumes. From Small Ball to LAG play and Short-Handed play, you will learn a variety of successful approaches to PLO.
Wherever you are on your PLO journey, one of the books above should help you advance your game.