This is the biography of a person about whom not many records exist. There are a couple of things others wrote about him and his son wrote a lot about him in his memoirs but he himself wrote very little about his life.
That obviously makes it hard to write a biography though it can be done. Unfortunately Reiss tries very hard to distract from the fact by giving a lot of background-information about the time Dumas lived in. Again that is not a bad thing. In fact one needs quite a good understanding of how society would treat the son of a white count with his black slave in that time but Reiss goes into a lot of detail. First into Dumas' family-history, then into the situation of slaves in France and the French Colonies at that time, then the French upper class and now we've reached the French Revolution...
At this stage I'm sure we spent more pages on the background than on Dumas himself. (It's not even that it's not interesting*...I just feel mislead as the cover promised a biography of Dumas)
*except for the bit on the French Revolution. Not that it's boring but I already read Mark Steels' take on it and this book doesn't offer anything new.