BOSTON (CBS)– Boston Marathon bombing survivors Patrick Downes and Jessica Kensky have written a new children’s book about their service dog Rescue.

The book, due out April 3, is called “Rescue & Jessica: A Life-Changing Friendship.” And it certainly has been.

READ MORE: Rally Calls For Asian Studies To Be Added To School Curriculum In Massachusetts

NEADS World Class Service Dogs, which trains dogs in Princeton, Mass., donated the black lab to Patrick and Jessica as they were recovering from their injuries; Jessica has lost both legs and Patrick lost his left leg.

READ MORE: Dorchester Grandmother Killed By Stray Bullet While Sitting On Porch Identified As Delois Brown

They discovered that Rescue, who was born in 2012, was not only able to physically help them with tasks, but that he became an emotional support animal, as well.

MORE NEWS: Water Conservation Urged In Massachusetts Amid Dry Spell

“I really didn’t anticipate how much he was going to be able to help us emotionally,” Jessica told Paula Ebben and Liam Martin during a live interview Friday night at 8 on myTV38. “I needed to take care of him like he took care of me; getting out of bed; exercising him; feeding him; it got me back on a routine; and just the joy he brought into our lives.”