I doubt the author has read any of the DC comic super hero Martian Manhunter, because there are many similarities to the comic and this book, and I doubt Mr. Allen would have written this if he'd known about the comic hero.
Some spoilers:
Both are aliens with super powers blending in to society acting a bit like a private investigator.... Justin aka Jalin (book), J'onn J'onzz (comic). Book has a chameleon-like feline who can turn invisible; comic has J'onn shape shifting and turning invisible. Book has Justin so smart he always knows/figures out/anticipates his opponents next move; comic has J'onn reading minds.
Overall, an enjoyable read. Good action, well paced. The biggest problem this novel has is the hero is too perfect. He has no challenges, and thus, there is no tension. He has more than enough money, has several safe houses stashed around the world, is smarter, stronger, faster, good looking, well trained, super experienced, two steps ahead of all the villains, the perfect teacher on many subjects, is generous with time and money, laughs in the face of danger (because there is no danger for him), has far-advanced technology aiding him even more, and sort of boring because of all of this.
The author has a great eye for details, although sometimes it felt like too many details, as if he was pointing out to me, the reader, at how much he observes in the real world. I'm teasing, mostly. There are a lot of details, and not all of them advance the plot, they're there for details' sake.
Obviously I liked the novel (4/5 stars), and I'm interested to see if any real challenges/threats come along for this character in the next two books of the series.