It’s an intriguing concept: Round up some of the best fantasy writers in existence and give them carte blanche to make up imaginary diseases. If the results, collected in The Thackery T. Lambshead Pocket Guide to Eccentric & Discredited Diseases, are occasionally a tad too Borgesian for my tastes, they’re still pretty darn entertaining. From Ballistic Organ Syndrome—a “sudden, explosive discharge of one or more bodily organs” that “may be accompanied by some pain”—to Third Eye Infection, the diseases in Lambshead’s guide are unlikely to afflict anybody you know (although you probably have friends who suffer from Pathological Instrumentation Disorder, a form of “extreme mental distress” that can only be alleviated by proximity to such hi-tech gadgets as Palm organizers, iPods, and the like). In addition to its stellar cast of contributing physicians—including Neil Gaiman, Rachel Pollack, and Michael Moorcock—the guide offers such features as a biographical sketch of Dr. Lambshead (who, in addition to his medical work, found time to do choreography for the Salvation Army Modern Dance Society) and an “obscure medical history of the 20th century” (which reveals that Adolf Hitler was actually a case of identical Siamese half-twins and that the sexual revolution was caused by saccharine). Throw in some great author bios—it turns out that “Dr.” R.M. Berry was known as the “Dwight D. Eisenhower of Marital Psychopharmacology”—and what you have is a book that you’ll treasure forever, or at least until you succumb to Hsing’s Spontaneous Self Flaying Sarcoma. Lambshead editors VanderMeer (pictured) and Roberts read with other contributors at 7 p.m. Thursday, Oct. 30, at Borders, 18th and L Streets NW. Free. (202) 466-4999. (Michael Little)