This book constitutes the refereed proceedings of the 7th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2001.The 36 revised full papers presented together with an invited contribution were carefully reviewed and selected from a total of 125 submissions. The papers are organized in sections on symbolic verification, infinite state systems – deduction and abstraction, application of model checking techniques, timed and probabilistic systems, hardware – design and verification, software verification, testing – techniques and tools, implementation techniques, semantics and compositional verification, logics and model checking, and ETAPS tool demonstration.