Great book for someone like me that does not have much of a background in how the Supreme Court actually functions. O'Brien's writing is mostly engaging and he covers a lot of material, including a quick and dirty history of the court, how the Justices interact, the process for deciding which cases to consider, how deliberations happen, and how the Court's staff has come to play an ever larger role in the Court's operations.
For veteran observers of the Supreme Court, maybe much of this is common knowledge. But for me, these were issues I had not given much consideration to, and I felt I had a significantly expanded and deepened understanding of the mechanics of the Court once I had digested this information.