At the heart of network synthesis is the concept of Positive Real functions, originally defined by Otto Brune. Van Valkenburg dedicates significant attention to teaching students how to test whether a driving-point impedance function
If you use a tool like Nuhertz FilterSolutions or even the built-in filter designer in KiCad, you are standing on the shoulders of Van Valkenburg.
4. Two-Port Network Synthesis and Transfer Function Approximation
The ultimate generalization of passive synthesis, incorporating all three basic components.
Here is what you will actually learn inside its pages: