Remember how two of the three books he wrote with his mom overlapped? Well, this one is exactly the same time as his first lone book, Dragonsblood. It's an almost completely different batch of people, but we know a bit about what happened to them at the end of the first book. He would certainly have a lot more to write about if he kept writing decent stories at the same time but different places and people. He's not nearly as bad as Piers Anthony was with Incarnations of Immortality.
He does introduce the equivalent of Arabs in this book. People with robes, scarves over their heads held by twisted ropes, travel in caravans, spicy food, etc. They claim to be able to track their history back to Earth. The two primary Arabs are in a lot of the book and turn out nice, but when they're first met, all of them seem a bit sneaky. I think he should have had someone look at that.
I'm going to read the next one -- last one out so far -- but I think I'll keep these. He does seem to be getting better.