It is common knowledge (at least to some) that Lovecraft revered the writing of Edgar Allen Poe, especially in his younger years. The Outsider is, next to In the Vault, probably his most Poe-like tale. While his references to Elder God-like beings keep it true Lovecraft, the influence is definitely there. This is one of the rare instances of Lovecraft's work where the surprise ending is actually very surprising... and disturbing! Highly recommended!