48. Darkest Fear Harlan Coben 2000
Hero is named Myron Bolitar and is an investigator/sports agent. Contracted to find bone marrow for a transplant for an old flame's son, who turns out to be his. Whilst accomplishing this, solves a series of murders. And signs a famous shortstop.
A real page turner; I sat up till 3am reading it.
I'm going to look for more Bolitar novels. His character is quite endearing.