"Twenty years of the Handbook of Metaheuristics: A retrospective" Michel Gendreau The publication of the first edition of the Handbook of Metaheuristics back in 2003 was an important event for the metaheuristics community, since, for the first time, one could find solid introductions to all major families of metaheuristics, written by top experts, in a single volume. The second and the third editions of the Handbook, published respectively in 2010 and 2019, have seen updated versions of most chapters, as well as new ones covering other facets of the field, thus keeping this important reference book current. In this talk, I will try to provide a guided tour of the three editions of the Handbook. I will first try to provide my own, subjective explanation of the genesis of the Handbook. This will be followed in turn by a description of the core chapters that have seen little changes from one edition to another and by explanations regarding the changes performed between the editions. Finally, I will try to explain, in a clearly subjective and biased fashion, why the Handbook has been and still is an important book for the metaheuristics community."