ALIEN STARS opens with Harry having lost his job with legitimate firms and having been reduced to doing criminal work with a corrupt partner. They now serve as thieves and black marketeers who acquire antiques with occult significance then sell them to their patrons. It's a pretty big shift for the normally honest and forthright Harry so I found this change a bit jarring. This time, his latest job results in a death of a young woman who is involved in a conspiracy to deal with an unnatural plague that can destroy the world.
Alien Stars isn't quite as enjoyable as the other two volumes of the series due to the fact Harry doesn't quite work as a professional criminal and I felt the more "aware" cultists helping him investigate the occult was less interesting than the protagonist stumbling around on his own. On the plus side, I liked the larger role of women in the story. There's more in this book and they play a more central role than usual. I also appreciate all the references to the Colour out of Space, which is my favorite of HPL's work.
I appreciate Harry's working class attitudes and how he's more worried about raising enough money to make it through next week than he is about the cosmic forces menacing the universe. I'm not sure it's believable he has as much trouble finding work as he does given the horrible casualties of both WW1 as well as the Spanish Flu. You'd think there'd be plenty of work for him to find but he's probably developing a bad reputation given all the uncomfortable things he's found himself involved with. I also appreciated some hints that Harry is contemplating his love life and the fact he's fallen into a relationship with a fallen woman.
The book also introduces Harry to some racist and occultist organizations that aren't immediately destroyed by the end of the book. I think they make an interesting contrast to Harry, who if not a progressive by modern standards, is certainly so for his time. I don't think he'll remain with his current employers long but am not sure how he'd be able to turn against them without getting himself killed. Harry is not a evil genius or guile hero, he's just a solid working class man who survives the Great Old Ones primarily by knowing when to run.
This book is also the first time Harry is actually attempting to stop one of the supernatural menaces he's found himself facing. Before, he's ended up dealing with issues sideways or existing on the peripherary of something supernatural. Here, there's a real threat to the world and it's interesting to see how Harry copes with it. Part of the books' charm is the fact he's not a hero but dealing with things that are potentially world-shaking. His bystander status (and continued survival) is one of the things which makes him almost unique in the Cthulhu Mythos.
In conclusion, this is a decent sequel to the previous Harry Stubbs novels and I recommend them to anyone who wants to continue the series. David Hambling has created a wonderfully complex occult detective mystery series that makes excellent use of its historical period.