Bruce Coville

When Grizelda decides to seek revenge on King Mildred by creating the largest, fiercest dragon in the kingdom, an unlikely trio of argumentative heroes--an elderly squire, a young page boy, and a headstrong, tomboy princess--set out to destroy it. Simultaneous.

The Search For Snout is the third book in the series Rod Allbright's Alien Adventures. It was written by Bruce Coville and first published in 1995. In the UK it was published under the title Aliens Stole My Dad.