AMERICAN AGENTMelvin H. PurvisDoubleday, Doran ($2.75).
Inhibited by the need for keeping professional secrets from criminals, officers of the law usually write books that have all the bad features of detective stories and none of their ingenuity. By no means so pompous in his professional recollections as Sir Basil Thomson, onetime chief of Scotland Yard (The Story of Scotland Yard), Melvin Horace Purvis, onetime head of the Chicago office of the Federal Bureau of Investigation, nevertheless falls into the literary ambush that has trapped so many of his predecessors, composing an account that contains...