Matti Juntunen (1943-1979) had many friends. He was known as a scientist and teacher especially at the universities of Jyvaskyla, Tampere and Turku. His friends and colleagues decided to dedicate this book to his memory. This book contains articles by Matti's teachers, colleagues and students. The first part of the book consists of articles by his teachers, the second part consists of "academic" articles by his colleagues and students and the third part contains articles of a more personal nature. There is not specific theme in this book. Instead, each writer deals with a subject of his own interest. The common aim of the writers has been a wish to honour the memory of Matti Juntunen.