Besides modularity, the technical treatment in Computational Gasdynamics distinguishes itself in other ways. Many textbooks stress linear and locally-linear methods. Yet CFD is moving progressively towards inherently nonlinear methods. The stress on linearity found in most basic CFD treatments has lead to confusion in the CFD community, even among experts. Unfortunately, many conclusions drawn for linear methods simply do not apply to inherently nonlinear methods.
Linearity greatly simplifies things, but at the cost of making the dissimilar seem similar.
Computational Gasdynamics is constructed from the ground up to treat nonlinear methods. The reliance on linear theory exemplifies the type of shortcuts taken by many books in their treatments of key topics. These commonly used shortcuts make things easier for the reader just at first, but a great deal more complicated immediately afterwards. For example, in many treatments, the CFL condition is often described first or only in the context of linear stability analysis. More specifically, at the end of a linear stability analysis of a simple method, the result is identified as being the CFL condition, which is true only coincidentally.