In the ?rst part of the present volume of LNCS, the reader will ?nd the invited talks given at the MCU 2001 conference. In the second part, he/she will ?nd the contributions that were presented at the conference after selection. In both cases, papers are arranged in the alphabetical order of the authors. MCU 2001 is the third conference in theoretical computer science, Machines, computations and universality, formerly, Machines et calculs universels. Both previous conferences, MCU'95 and MCU'98, were organized by Maurice M- genstern in Paris and in Metz (France), respectively. From the very...