冷血悍将(Without Remorse)简介：
Without Remorse is a thriller novel published in 1993 by Tom Clancy and is a part of the "Ryanverse" series. While not the first novel of the series to be published, it is first in plot chronology. The main setting of the book is set during the Vietnam War, in the American city of Baltimore. The book focuses on the development of one of Clancy's recurring characters, John Kelly/John Clark, while providing the character some back-story. The book serves to give a history of Kelly's life, and explains how he becomes John Clark.

The book alternates between multiple story arcs, involving: Kelly's back-story and his personal crusade against a large drug ring responsible for killing his girlfriend Pam; the capture and imprisonment of United States Air Force colonel Robin Zacharias in a POW camp; major heroin dealer Henry Tucker, his Mafia connection Tony Piaggi, and their employment of a corrupt policeman named Mark Charon. Other story arcs in the book introduce characters such as detective Emmet Ryan (the father of Jack Ryan, who makes a brief appearance in the book) and his partner who are investigating the recent murders of a string of drug dealers.