This Festschrift volume, published in honor of Yuri Gurevich on the occasion of his 70th birthday, contains contributions, written by his colleagues. The collection of articles herein begins with an academic biography, an annotated list of Yuri's publications and reports, and a personal tribute by Jan Van den Bussche. These are followed by 28 technical contributions. These articles - though they cover a broad range of topics - represent only a fraction of Yuri Gurevich 's multiple areas of interest.