Galactic Patrol (version 2) by E. E. Smith

Galactic Patrol is the third book in the Lensmen stories, and the first book to feature Kimball Kinnison, the action hero of several books in the series. It chronicles the beginning of Kinnison's adventures, starting with graduation from the Galactic Patrol Academy and becoming a Lensmen. Kinnison then pursues the Boskonians, a group of galactic pirates who are wreaking havoc. - Summary by Harley James