New York is sweltering in the summer heat, and Harlem is dose to the boiling point. To Coffin Ed Johnson and Grave Digger Jones, at times it seems as if the whole world has gone mad. Trying, as always, to keep some kind of peace-their legendary nickel-plated Colts very much in evidence-Coffin Ed and Grave Digger find themselves pursuing two completely different cases through a maze of knifings, beatings, and riots that threaten to tear Harlem apart. ''The word is out on the street, and the hopheads and whores and flimflam artists are running scared: Coffin Ed Johnson and Grave Digger Jones are back in print.''-- Newsweek