The Croning by Laird Barron

Strange things exist on the periphery of our existence, haunting us from the darkness looming beyond our firelight. Black magic, weird cults and worse things loom in the shadows. The Children of Old Leech have been with us from time immemorial. And they love us...
Donald Miller, geologist and academic, has walked along the edge of a chasm for most of his nearly eighty years, leading a charmed life between endearing absent-mindedness and sanity-shattering realization. Now, all things must converge. Donald will discover the dark secrets along the edges, unearthing savage truths about his wife Michelle, their adult twins, and all he knows and trusts. For Donald is about to stumble on the secret...
...of The Croning.
From Laird Barron, Shirley Jackson Award-winning author of The Imago Sequence and Occultation, comes The Croning, a debut novel of cosmic horror.