The Inadequate Adept by Simon Hawke

The Voice in the Ether...

Trying to discover time travel, scientific genius Dr. Marvin Brewster accidentally transports himself to a parallel universe that suspiciously resembles the setting of a fantasy novel ... a strange, medieval world where magic really works, unicorns hate virgins and smell terrible, elves drink human blood and play guitars, dwarves wear dreadlocks and flannel plaids, talking dragons dream our universe, and sorcerers are powerful enough to detect the presence of the narrator and attempt to take over the plot.

Trapped without his time machine, which has mysteriously disappeared, Brewster enlists the aid of the residents of Brigand's Roost to help him find it, in exchange for bringing some progress to their village in the form of solar power, showers, prescription lenses, a wondrous, alchemical concoction he calls "soap," and a strange, lightweight metal called "aluminum."

However, any science that is sufficiently advanced would seem like magic to those who didn't understand it, and the Sorcerers and Adepts Guild takes a dim view of anyone who practices magic without paying their dues ....