This book is dedicated to Professor Martin Wirsing on the occasion of his emeritation from Ludwig-Maximilians-Universität in Munich, Germany. The volume is a reflection, with gratitude and admiration, on Professor Wirsing’s life highly creative, remarkably fruitful and intellectually generous life. It also gives a snapshot of the research ideas that in many cases have been deeply influenced by Professor Wirsing’s work.The book consists of six sections. The first section contains personal remembrances and expressions of gratitude from friends of Professor Wirsing. The remaining five sections consist of groups of scientific papers written by colleagues and collaborators of Professor Wirsing, which have been grouped and ordered according to his scientific evolution. More specifically, the papers are concerned with logical and algebraic foundations; algebraic specifications, institutions and rewriting; foundations of software engineering; service oriented systems; and adaptive and autonomic systems.