[2][3] Part IV, "the highlight in this book", proves the classification of finite reflection groups and of root systems.
[3] The final part of the book studies in more detail and through more elementary methods the three-dimensional finite reflection groups and the symmetries of the regular icosahedron.
Appendices provide suggestions for mathematical visualization, and list hints and solutions for exercises.
[2] Mirrors and Reflections is aimed at undergraduate mathematics students, and uses an intuitive and heavily visual approach suitable for that level.
[1][2] Reviewer Gizem Karaali recommends the book, both as a textbook for a "capstone" undergraduate course, and as individual reading for students interested in this topic.