The two volumes of “Crossovers” are a fascinating and highly enjoyable read for anyone interested in the interactions between various pulp, mystery, adventure, and science fiction characters with each other and real people throughout history. The premise of the book was inspired by SF writer Philip José Farmer’s “Wold Newton” concept which he developed in the 1970s: a “radioactive” meteorite crashed near Wold Newton, England, in 1795 and affected several carriages full of people who were passing by. Their descendants became highly intelligent and powerful heroes (or villains) such as Sherlock Holmes, Professor Moriarty, Dr. Fu Manchu, Doc Savage, Lord Greystoke (Tarzan), and many more. Farmer wrote popular and detailed biographies of Tarzan and Doc Savage in which he explored the family trees of many “Wold Newton Family” characters. Over time, the concept has been expanded and continued by Win Scott Eckert and others to become the “Crossover Universe.” Mr. Eckert has done a fantastic job of compiling references to literary heroes who have met each other (or “crossed over”) and had adventures together, and thus co-exist in the same fictional universe. Volume 1 covers the dawn of time up through 1939, and Volume 2 covers 1940 into the far future. (Mr. Spock himself claimed Sherlock Holmes as an ancestor of his!) There are 2000 entries in this chronology and 300 illustrations. Reading these two books is fun and will send you scurrying to find many of the stories and books that are referenced.