I'm currently reading the old Panther edition of "Other Dimensions" (Vol 2). In this one, I have found examples of stories which fit more correctly into the sci-fi genre. On occasion, I have noticed references to ancient Greek times (e.g. the term for a Greek warship is used for example). I would classify the majority of his stories though, as "fantasy horror". Unlike HP Lovecraft, CAS does not seem afraid to use graphic language when he is describing a violent or horrific situation. In contrast, HP Lovecraft normally used suggestion in order to convey such scenes to the reader.

Julian L Hawksworth

Welcome to the amazing adventure - dive deeply.

Dr. Farmer

And what a place to start. A highly collectible paperback (the only Panther I haven't got yet).

While it might be collectible, I can think of any number of other titles that would make a better introduction for the neophyte reader. Still, welcome!
When one speaks of Smith's style, it is important to consider just what type of story he was setting out to write. He used a distinct style for his stf stories, another for his modern horrors, a third for his secondary world tales (and these could vary tremendously, from the brooding sense of impending doom in Zothique to the drolleries of Hyperborea), and a fourth, which I'd call "exercises in deliberate archaism," for tales such as "A Tale of Sir John Maundeville" and "The Ghoul." Smith was very much in control of his writing at all times, and could select from a wide repetoire when he so desired.

Best,
Scott