My father, Shimon Even, died on May 1, 2004. In the year prior to his illness, he began revising this book.He used to tell me with great satisfaction whenever he completed the revision of a chapter. To his surprise, he often discovered that, after twenty-five years, he preferred to present thematerial differently (the first edition was published in 1979). Unfortunately, he only managed to revise Chapters 1, 2, 3, and 5. These revised chapters appear in this edition. However, since the material in Chapters 9 and 10 on NP-completeness is well covered in a few other books, we decided to omit these chapters from the second edition. Therefore, the second edition contains only the first eight chapters.

As I was reading the manuscript for the second edition, my father's deep voice resonated clearly in my mind. Not only his voice, but also his passion for teaching, for elegant explanations, and, most importantly, for distilling the essence. As an exceptional teacher, he used his voice and his physique to reinforce his arguments. His smile revealed how happy he was to have the opportunity to tell newcomers about this wonderful topic. One cannot overvalue the power of such enthusiasm. Luckily, this enthusiasm is conveyed in this book.

Many people tell me (with a smile) about being introduced to the topic of algorithms through this book. I believe the source of their smiles is its outstanding balance between clarity and preciseness. When one writes mathematical text, it is very easy to get carried away with the desire to be precise.