Under Consideration for Publication in Theory and Practice of Logic Programming Book Review

Constraint programming is a very active research area that lies at the intersection of AI, OR, Programming Languages, Data Bases, and Graph Theory, and whose main aim is to model naturally and solve efficiently real-life problems that can be cast as a set of objects and a set of restrictions (that is, constraints) on how these objects can co-exist in the same problem. Constraint programming started a long time ago, with the first propagation algorithms by Waltz, Montanari, Mackworth and Freuder in the late 70’s, then it found high-level language support in Constraint Logic Programming (CLP) in the late 80’s, and since then it has evolved to a very complex discipline with many different modeling languages and solving techniques. K. R. Apt’s book on constraint programming (Apt, 2003) has been published in 2003 and is thus one the latest books published on this subject. To be able to contextualize the value of this book, we first need to draw a brief history of the books that have been published on this same subject. The first book on constraint programming was published in 1989 (Hentenryck, 1989) by Pascal Van Hentenryck, and it showed how to exploit some of the constraint techniques typical of AI in the CLP world, by using the CHIP language. A few years later, in 1993, Edward Tsang wrote a book on constraint solving (Tsang, 1993), which contained the main notions as well as some advanced solving techniques based on local search and genetic algorithms. This book had an AI flavor, and did not deal with programming languages based on constraints such as CLP. In the same year, Vijay Saraswat published a book on Concurrent Constraint Programming (CCP) (Saraswat, 1993), a concurrent abstract model of computation, originated from extensions of CLP, where constraints are not only a way to express real-life restrictions, but also a way for concurrent agents to communicate. Van Hentenryck’s book was a good source of information for CLPers, but as time passed new techniques, propagation algorithms, and language constructs were proposed, so the book on CLP by Marriott and Stuckey (Marriott & Stuckey, 1998), that appeared in 1998, updated the readers by containing the basic notions of constraint propagation, and by also giving a formal syntax and semantics of the current computational model of CLP. So, by 1998 people knew where to find the main notions and results of constraint solving, as well as the syntax and semantics of constraint programming languages like CLP and CCP. However, what was still missing was a place where to find also the most