Strange Eons is Robert Bloch's homage to his old mentor and correspondent, H.P. Lovecraft. Taking names and incidents mentioned in Lovecraft's tales, Bloch (best known for the novel Psycho) weaves a story surrounding three individuals who run afoul of the otherworldly monsters of the so-called Cthulhu Mythos. (In brief, the Cthulhu Mythos is the name given to a fragmentary mythology as reflected in most of Lovecraft's fiction; he posits an array of godlike beings so horrible and alien to human conception that running into one is likely, even if one is lucky enough to survive the encounter, to drive a person insane. Cthulhu, a giant being with the head of an octopus, is the most well-known of these creatures.)
The title is taken from a famous Lovecraftian couplet: "That is not dead which can eternal lie/ and with strange eons, even death may die." The story begins when Albert Keith, an eccentric art collector, purchases the literally ghoulish painting described in Lovecraft's story, "Pickman's Model." From that point, he (and others) begin to deduce that Lovecraft's stories were not fiction, but thinly-disguised prophecies and warnings to the human race. As they investigate, the novel gives us a kind of Cliffs Notes overview of Lovecraft's major themes.
Bloch's novel is fast-paced, which is unusual for this kind of supernatural fiction. Typically, atmosphere and evocative description dominate, neither of which necessarily lend themselves to quick reading. This marks the book's biggest departure from Lovecraft's style and tone, but what he loses in 'period authenticity', Bloch makes up for in plot twists, with each new revelation uncovering another Lovecraftian icon--the Shining Trapezohedron, or the people from Innsmouth. Added to that is Bloch's gift for naturalistic dialogue (a gift Lovecraft himself lacked) and characterization.
The biggest problem with the novel is deciding who its audience is. Die-hard Lovecraft fans might not like the direction Bloch took with some characters (such as a hip, jive-talking preacher--the book was written in the '70s, after all), nor would most of them need to have the background explained to them. Those unfamiliar with Lovecraft might wonder why so much of the book is devoted to someone else's writings. Nonetheless, the solidity of the plot and the fast pace of the storytelling are worthwhile in their own right.
If you're a fan of Lovecraft and don't mind the radical departure in tone, or are a fan of supernatural investigation in general, Strange Eons is a great short read and a tribute to the man who gave Bloch so much inspiration in his early days.