This book provides a very short overview of Roman law, focusing on the historical sources of Roman law. It is mostly concerned with private law, although the first chapter discusses public and constitutional law.
I found the book to at times seem more like listening in on an academic conference about Roman law than reading a book. Very often, Robinson cited sources or other academics without explanation. Near the end, she discusses other historians' arguments, as if the reader is in on the game. At the very end, she seems to take a jab at another historian whose treatise on Roman literature ignored law. As such, this book is probably more appropriate for somebody who had read mass market book or taken a class on Roman law first.
I also thought Robinson's writing style was a bit long-winded. Many of the sentences were far too long, with semicolons placed in between what should have been separate sentences. This, in addition to the book's depth, made it a bit difficult to read. If you do read it, I think you'll find some interesting points, but it could have been made more accessible.