During the second half of the 1950s, folks derisively referred to the Kansas City A’s as a “farm team” of the New York Yankees. Trades between the two—often lopsided—were commonplace, and it seemed every time the Yankees needed that one final piece for yet another pennant run, the A’s filled the gap. While most knew that A’s owner Arnold Johnson was somewhat affiliated with Yankee owners Dan Topping and Del Webb through his joint ownership of Yankee Stadium, The Kansas City A’s and the Wrong Half of the Yankees digs into the deeper business entanglements among the three. In addition to the questionable trades and his earlier purchase of “The House that Ruth Built,” Johnson’s purchase of the then–Philadelphia A’s shows signs of Yankees clout. Through periodicals,A letters, conversations with contemporary players and executives, and an analysis of player records, author Jeff Katz has...