"Books have their destinies." In the preface to the complete work, which was presented in 1941 before the first volume of this handbook, the intention was expressed and justified to create a simultaneous cross-section of the field of catalysis and therefore to complete the entire work as quickly as possible. Initially, this seemed to succeed, as volumes I to IV, VI, and VII were published by 1943 despite all the difficulties of the war years. However, historical events began to overpower the situation, and the already advanced preparations for the missing volume V had to be put on hold. The editor and the publisher are pleased that after 13 years, the gap can now be closed, not least due to the dedicated work of the authors, who have completely revised their old manuscripts in part. Of course, research continues.