BOSTON (CBS) – Boston Marathon Race Director Dave McGillivray makes it look easy, whether he’s running his age in miles or tackling 7 marathons in 7 days around the world. Recently, McGillivray released his first children’s book.

“When I was little, I was little,” McGillivray said. “But I had big dreams.”

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That dream was to be an athlete and at 5’4” Dave McGillivray is a giant in the running world.

Dave McGillivray (WBZ-TV)

In “Dream Big” McGillivray explains he was rejected as “too small” for most teams. He started running because there were no tryouts. And with his grandfather’s encouragement, he set his sights on the Boston Marathon.

“I finished it in 1973 and I said I’m gonna run this race every year for the rest of my life in honor of my grandfather and what he taught me about earning the right to do these sorts of things,” McGillivray said. “And I’ve run it now for the past 45 years.”

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He has encouraged a lot of other runners.

Scott and Jack Middlemiss (WBZ-TV)

Scott Middlemiss crossed the finish line in 2016 with his little boy, Jack. Jack’s older brother, Joey died of cardiomyopathy.

The family’s Joseph Middlemiss Big Heart Foundation is buying McGillivray’s book for hundreds of kids in Greater Boston.

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Jack Middlemiss just had a heart transplant. For the little boy who loves medals, McGillivray sent home a special gift: seven marathon medals from his races around the world.