Atomic physics, statistical physics, molecular spectra, crystal structure, and lattice dynamics. Chapters 12–16
: Special Theory of Relativity, Wave-Mechanical Concepts, and General Principles of Quantum Mechanics. Atomic & Molecular Physics
from the book’s syllabus (e.g., Compton effect, Schrödinger equation, band theory, lasers, etc.)
Start with Chapter 1 (Relativity) and Chapter 2 (Radiation) to understand why classical physics failed and why "modern" theories were necessary .