Blood Work is a 1998 mystery thriller novel written by Michael Connelly which marks the first appearance of Terry McCaleb.

Retired FBI profiler Terrell "Terry" McCaleb, the recent recipient of a heart transplant, is contacted by Graciela Rivers, the sister of his donor Gloria, and asked to investigate her death in an unsolved convenience store robbery.

Because of this, the police on Gloria's case focus on Terry as the possible killer and get a warrant to search the fishing boat where he lives.

He then finds and is overpowered by the Code Killer, who tells him that he has kidnapped Graciela and Raymond and buried them alive.

Despite serious medical problems from so much activity, Terry is able to kill the Code Killer and then uses the little information he has to locate and rescue Graciela and Raymond.