A Malady Of Magicks by Craig Shaw Gardner

A genial but hapless wizard develops a bizarre allergy to magic that makes spellcasting impossible and sends him and his reluctant companion into a string of farcical misadventures; forced to rely on cleverness, mundane skills, and awkward diplomacy rather than sorcery, they bumble through court intrigues, thwart bumbling villains, and unravel the mystery behind the malady in a lighthearted satire of fantasy tropes full of witty dialogue and slapstick situations.

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