Dog siblings Harlow, Sage and Indiana are so popular on Instagram that they felt it was time to write a book called "Harlow & Sage (and Indiana): A True Story About Best Friends."

The book is told from Harlow the miniature dachshund's perspective, detailing her journey of bonding with her big sister and best friend, Sage. Harlow highlights the good times looking up to her big sister, but also talks about what it was like dealing with her death after Sage turned 13. 

When Indiana, a new younger sister, comes into the picture the roles change in Harlow's life and she realizes it's her turn to play the role of big sister to Indiana and her next big adventure is about to begin. 

The book is written for all ages and is suggested by author Brittni Vega, who is also the pups' human mother, for families with young children and pets. 

If you haven't met these famous pups yet - or just can't get enough of them - here are some pictures of the adorable sisters: