I really enjoyed reading Hans Kellerer, David Pisinger, Ulrich Pferschy 2004 book Knapsack Problems. Can anybody recommend books in a similar style, about some other classes of problems / optimisation?
I waited some time but apparently no easy answer here. Thanks for providing some more hints in the comments to your question. One specialty about the knapsack book is: it is a monograph, that is, written by the same author(s). There are only few other books about a particular combinatorial optimization problem, with theory and algorithmic components, and precise in the mathematics, and the "LPs are used" portion.
A brilliant example is In Pursuit of the Traveling Salesman - Mathematics at the Limits of Computation by Bill Cook.
Often, books are collections, that is, they are edited by a small number of researchers, but the single chapters are written by different people, and thus usually differ in style and presentation; usually, there is not much coherence in terms of cross references among chapters etc.
One example is the area of vehicle routing, with books like The Vehicle Routing Problem by Golden et al., or Vehicle Routing: Problems, Methods, and Applications by Toth and Vigo.