A free undergraduate textbook on quantum theory, suitable for a first course.
Fundamentals of Quantum Theory is an open educational textbook for a first course in quantum theory, bringing together rigorous formalism, conceptual foundations, and guided introductions to modern quantum science. It was written for those of you who, like us, live at the banana scale but want to try to make sense of the quantum world.
Inspired by the Quantum Information and Foundations of Quantum Mechanics courses taught at Imperial College London between 2009 and 2016, and considerably enhanced over many years by the two authors, Fundamentals of Quantum Theory is guided by the following principles:
1. The latest edition of this book will always be accessible for free online, and for the printed version we won't charge any royalties.
2. Your feedback as a student or a teacher (at any level of detail) will be crucial to make this book a useful tool for everyone. Please do contact us with any comments, criticisms, questions, suggestions, nice recipes at