In May 1998, India and Pakistan put to rest years of speculation as to whether they possessed nuclear technology and openly tested their weapons. Some believed nuclearization would stabilize South Asia; others prophesized disaster. Authors of two of the most comprehensive books on South Asia's new nuclear era, Sumit Ganguly and S. Paul Kapur, offer competing theories on the transformation of the region and what these patterns mean for the world's next proliferators.

Ganguly begins with an outcome-based approach emphasizing the results of militarized conflict. In his opinion, nuclear...