Enimnori:Discovery (book 2)

Can a modern engineer survive in a world where magic is real?
 
A man from the modern world, Scott Hathaway, an electronics engineer with a penchant for martial arts, has been transported to another world where magic is real. He becomes friends with his accidental summoner, Brandon, and Brandon's mentor, master magician Morgan. The two magicians become embroiled in a battle to protect their home. Scott, not wanting to see his new friends killed or enslaved, teaches them how to make gunpowder. Grateful, they organize an expedition to find more of the special crystals that enhance their power in an attempt to send him back to his own world and family. Now they must brave the dangers of an almost unknown wilderness and face whatever they find at the end of their journey.