This fascicle inaugurates the eagerly awaited publication of Knuth's 'The Art of Computer Programming', Volume 4: Combinatorial Algorithms. Part of what will be a long chapter on combinatorial searching, the fascicle begins his treatment of how to generate all possibilities. Specifically, it discusses the generation of all n-tuples, then extends those ideas to all permutations. Such algorithms provide a natural motivation by means of which many of the key ideas of combinatorial mathematics can be introduced and explored. In this and other fascicles of Volume 4, Knuth illuminates important theories by discussing related games and puzzles. Even serious programming can be fun.