This is an oddity in the James Ellroy catalogue: it contains a mixture of novellas, set in context by Ellroy, memories of his mother's murder and his childhood, and some articles he wrote for GQ.
As a mixture it didn't really hang together well for me, but the comments surrounding the novellas were interesting. The critique of the OJ Simpson trial also held my interest, knowing how the trial actually turned out.
As an introduction to Ellroy, I wouldn't recommend this, but if you're a fan, he provides some greater context and insight into his influences and formative years.
My Dark Places details much better his feelings and thoughts on his mother's murder, but this book shows his overall feel and approach to "cold cases".
As a throw away almost, at the end of the book, he gives his take on the big screen adaptation of LA Confidential, another glimpse into his take on life and his work.