Rebekah Gregory

Rebekah Gregory, 29, scrambles to her feet and scoops up 10-month-old Ryleigh from the playroom floor.

"Let's go outside," she tells her daughter and deftly steps over the baby gate, moving with ease toward their Fulshear home's sunny backyard.

Her knee-length dress doesn't even attempt to cover up her artificial leg, a silver-and-black prosthesis that attaches just below her left kneecap.

Much like her leg, Gregory's whole life looks nothing like it did four years ago. On April 15, 2013, a bomb exploded next to her near the Boston Marathon finish line.

Since that afternoon, she has endured dozens of surgeries, including an amputation. She has learned to walk - to run, even - with an artificial leg. She has married, divorced, married again and given birth to a daughter. And as of Tuesday, she will have published a book: "Taking My Life Back: My Story of Faith, Determination, and Surviving the Boston Marathon Bombing," co-written with Anthony Flacco. CLICK FOR MORE