The Dragons of Blueland by Ruth Stiles Gannett
Trade paperback format. Illustrated by Ruth Chrisman Gannett. Highly recommended! Read the rest of the series, too -- My Father's Dragon, and Elmer and the Dragon.
The third volume of the "My Father's Dragon" trilogy, this adventure may be enjoyed on its own. Here, the baby dragon summons Elmer to help save his family from hunters.