Joe McGinniss, who had set out to chronicle a case of unjust prosecution [in Fatal Vision], changed his mind.

But he didn't tell MacDonald. How in the world could he? McGinniss had lived with MacDonald during his murder trial, and later, during one of MacDonald's preliminary stints behind bars, McGinniss lived in MacDonald's Southern California condo, drank his beer, watched his sunsets and went through his papers. He changed his mind—and went on writing. Consequently, we have here a kind of double story: the story of a killer being inched toward conviction by former supporters who have changed their minds and the story of a writer torn between conflicting moral obligations…. McGinniss scarcely mentions his dilemma—what moral allegiance is owed to a triple murderer, anyway?—yet it has affected the way he put this book together.

McGinniss keeps himself in the wings and gives center stage...