Book excerpt: This book is the first of the series of reference books I am working on, with the aim to provide a possibly most comprehensive review of methods developed in the field of Genetic Algorithms. The necessity to concentrate on certain thematic areas is the result of the character of these books. The choice of those areas, even though performed arbitrarily will hopefully reflect their degree of importance and popularity. Hence, in this book which begins the whole series, an operator of the greatest importance for Genetic Algorithms will be presented i.e. crossover operator and its area of application will be single objective numerical optimization problems. This edition contains descriptions of 11 standard, 66 binary coded, and 89 real coded crossover operators; 182 algorithms in a form of pseudo code; and 453 active URLs pointing to sites with referenced papers. My Internet page (www.tomaszgwiazda.pl) offers the first 40 pages of this book. You can also find a review written for Polish edition of my work.