Brett Schulte has posted on Robertson's Back Door to Richmond, on the Bermuda Hundred campaign.
I very much enjoyed the book, its analytical cast, and its revision of the Butler guilt trip laid on by those who thought he should have taken Petersburg; Robertson thought that Butler was a victim of diffuse guidance. He also made Butler look good compared to his corps commanders, Gillmore and Smith.
IIRC, in a series of Usenet posts some time ago, Grant biographer Brooks Simpson, however, took aim at Robertson's reconstructions of the Grant-Butler communications on mission/operations matters, arguing that Robertson had overreached his material. Butler should not have been confused.
Keep a close eye on Robertson's handling of the communications evidence. It may be a balancing act that fails but it will well repay careful reading with the pleasure only a compact historical problem can deliver.