First: I'm no expert in optimization, and this might be one reason why I did not like this book that much. I also skipped a good portion of the book, which I considered not being relevant for my work. One of the main drawbacks of this book is that, although the title speaks of combinatorial optimization, the topic is (integer) linear programming. I would have preferred at least a few chapters on nonlinear integer problems.
Chapter 2 concerned the simplex algorithm and was a pleasure to read. Chapter 3 dealt with the dual of a program, a concept which still escapes my understanding. I skipped Chapters 4-7 which concern the primal-dual algorithm and implementations (nowadays, I think LPs are solved using computer software). After a brief introduction to Landau's notation and complexity in Chapter 8, there are again three chapters devoted only to algorithms. I would have preferred a more rigorous treatment of matroids in Chapter 12; the chapters on integer LPs and the cutting-plane algorithm were excellently written. Chapters 15 and 16 introduce NP-complete problems, and Chapter 17 suggests approximative algorithms. Very interesting is again Chapter 18, which is almost exclusively devoted to the branch-and-bound method. Chapter 19, on local search, is exemplary for the overall appearance of the book: It is so full of examples that the big picture does not come across.