Presents mathematical methods for modelling parallel computer architectures, based on the results of ESPRIT's project 415 on computer languages for parallel architectures. Presented here are investigations incorporating a wide variety of programming styles, including functional, logic, and object-oriented paradigms. Topics covered include Philips' parallel object-oriented language POOL, lazy-functional languages, the languages IDEAL, K-LEAF, FP2, and Petri-net semantics for the AADL language.