In Between Dragons

Description for IN BETWEEN DRAGONS by Michael Kandel:

WELCOME TO MR. MCGULVEY'S MAGIC LIBRARY...

...where each book Sherman Potts reads is literally the door into a whole new world. In the poisoned city Cuspidor, valiant Sir Sherm faces the treacherous toxic dragons. In an imperiled Washington, D.C., psychic Sergeant Sherm faces the sinister psi-fiend from dimension X. On the distant planet of New Batavia, intrepid Commander Sherm confronts a cake-snatching demon from beyond space. But some adventures just aren't enough, so Sherm finds a way to add a little spice to Mr. McGulvey's library with and addition all his own. What he doesn't realize is that one little addition could have world-shattering implications. And now just plain Sherm must battle bravely to keep reality from destroying Mr. McGulvey's library---and vice versa!