At first glance, the title—Alex Cross's Trial—is kind of a no brainer. Alex Cross is the purported author of the book, and the story centers on the trial against the White Raiders. So boom, right? Next question, please.
But not so fast. While much of the plot focuses on the trial in the courtroom, there are multiple trials taking place in this book. Here we can think of trial not in the legal sense, but as a test. Ben certainly goes through a trial, choosing to confront the racism in his hometown head-on, and Abraham and the Black residents of the Quarter are definitely in an ongoing trial as racism does its best to ruin their lives. So the trial referred to in the title isn't restricted to the one Judge Corbett presides over; being tested is a central theme in the book in general.