256 page mass market paperback titled THE MAD GOBLIN/ LORD OF THE TREES by Philip Jose Farmer/ Ace Double # 51375, First printing, Copyright 1970 (75 cents cover)/ The Mad Goblin is an American novel by Philip Jose Farmer. Originally released in 1970, it was one of two intertwining sequels to Farmer's previous A Feast Unknown, along with Lord of the Trees. The Mad Goblin features Doc Caliban, an analogue of Doc Savage, as the main character. The novel was later retitled Keepers of the Secrets. Lord of the Trees features Lord Grandrith, an analogue (or "Tarzanalogue") of Tarzan, as the main character. At the end of A Feast Unknown, Grandrith and Doc Caliban (a thinly disguised Doc Savage) cease fighting each other upon learning that their personal war and indeed their entire lives were engineered by the Nine, a megalomaniacal and powerful secret society. The two men have a sexual affliction in common; they are impotent except when performing acts of violence; a temporary side effect of a serum that grants them eternal life—another product of the Nine. Angered by the ways they have been manipulated, the two heroes split up to overthrow the Nine, ultimately meeting up at the end. Lord of the Trees shows the story from Grandrith's point of view. The Mad Goblin tells the same story from Doc Caliban's viewpoint. During the events of the book, Grandrith kills two of the Nine, Mubaniga and Jiizfan. The oldest member of the Nine, XauXaz, died previously of extreme old age in A Feast Unknown. Iwaldi, The Mad Goblin, is also killed. In the end, only five of the Nine remain alive.

The book is complete and in VERY GOOD condition with some overall wear. The inside pages are tanning. Great cover art by Gray Morrow!