Most students fail Comms because they fail the math. Grami doesn't avoid math, but he filters it. He focuses on the essential transforms (Fourier, Laplace, Z) and probability theories specifically needed for modulation and detection. He doesn’t ask you to derive the math; he shows you how the math applies to the signal.
The textbook typically follows a 12 to 14-chapter structure (depending on the edition) covering the entire communication chain: Foundations introduction to digital communications ali grami pdf