Sourdough is bol­stered with the prequel novella The Suit­case Clone, never before avail­able in print. The new edi­tion of Mr. Penumbra’s 24-Hour Book­store like­wise has the pre­quel Ajax Penumbra 1969 bun­dled in, along with a new fore­word from Paul Yamazaki, the leg­endary City Lights book­seller who could eas­ily be a char­ac­ter from the novel. He might, in fact, out-Penumbra Mr. Penum­bra.