The allied concepts of systems engineering and soft systems work, methodologies even, rely on concepts of explicit models of the domain under study. Pidd's thoughtful work here in clarifying the various types of meaning that may be included in a model, and what types of results can be gleaned from such abstractions is valuable for serious workers in these fields.
Some aspects of this 2nd edition are showing their age. The software-related chapters, as ever in works like this, need to be taken with a pinch of salt but there's no mention of what have now emerged as core concepts such as for example UML or genetic/evolutionary algorithms.