Yes, you absolutely need this book in digital form. A PDF version is superior for nonlinear control because you can quickly search for terms like "center manifold" or "Barbalat’s lemma," zoom in on complex equations, and have it open alongside your simulation software.
Nonlinear Control by Hassan K. Khalil: A Definitive Guide For students and practitioners of control theory, serves as one of the most authoritative and comprehensive resources in the field. Often sought after as a PDF or reference text, this work provides a rigorous yet accessible introduction to the analysis and design of nonlinear systems. Overview of Khalil’s Nonlinear Control nonlinear control khalil pdf