Lassie Come Home

Lassie Come Home by Eric Knight (Contains Affiliate Link)

Lassie is Joe's prize collie and constant companion. But when Joe's father loses his job, Lassie must be sold. Three times she escapes from her new owner, and three times she returns home to Joe, until finally she is taken to the remotest part of Scotland―too far a journey for any dog to make alone . . . But Lassie is not just any dog.

A Dog's Purpose

A Dog's Purpose by W. Bruce Cameron (Contains Affiliate Link)

The humor is real and effortless. You will find yourself laughing out loud. You will also cry. Real tears born out of your life's memories of pets past and the essential intertwining of souls that exists in no other relationship. (From Amazon.com product listing)

Dog Years

Dog Years by Mark Doty (Contains Affiliate Link)

When Mark Doty decides to adopt a dog as a companion for his dying partner, he brings home Beau, a large, malnourished golden retriever in need of loving care. Joining Arden, the black retriever, to complete their family, Beau bounds back into life. Before long, the two dogs become Doty's intimate companions, and eventually the very life force that keeps him from abandoning all hope during the darkest days.
Dog Years is a poignant, intimate memoir interwoven with profound reflections on our feelings for animals and the lessons they teach us about living, love, and loss. (From Amazon.com product listing)