If you need to an accessible and at the same time rigorous book on the kinetic theory of rarefied gases, with an in-depth discussion on classical and modern methods to derive macroscopic equations from the Boltzmann equation, you should probably read Henning Struchtrup book Macroscopic Transport Equations for Rarefied Gas Flows, published by Springer, and also available in electronic format. The book also targets non-experts of the topic, with an introduction to the basics of the kinetic theory, the derivation of the Boltzmann equation, an explanation of the Chapman-Enskog and Grad’s methods, the regularized Grad equations, to conclude with the order of magnitude approach and the study of the stability of the equations, of shock waves and other classical problems.
Enjoy you reading! 🙂