This book is very suitable as a textbook, but its writing style is not suitable for self-study. It needs to combine with the teacher's detailed formula deduction in the classroom to compliment the author's lack of deduction details, but this does not affect the value of this book as an introduction to beginners. This book is consistent in spirit in the deduction of harmonic oscillations and angular momentum, and at the same time has a good explanation of Dirac notation. This is of great help to students who study quantum chemistry but want to further understand quantum mechanics. Traditionally, quantum chemistry is more focus on wave functions than matrix mechanics, but the principles of molecular spectroscopy and the application of computational chemistry (such as NMR and DFT), Dirac notation and density matrix are too important. Dirac notation is often a major obstacle for students with chemistry background.<br><br>It is recommended to read with R. Shankar's book.