Doug Merlino didn’t know much about MMA the first time he saw the sport. But after spending two years embedded with American Top Team, he penned one of the most in-depth accounts to date of life in the sport. Merlino, a Washington native, was living in New York City in 2010 when a neighbor began talking to him about MMA. That neighbor took Merlino to a bar to watch “UFC 114: Rampage vs. Evans,” and while the main event featured a grudge match between two UFC superstars, it was the infamous heavyweight contest between Mike Russow and Todd Duffee that stuck with the author well after the event. “I left the bar energized,” Merlino wrote in his new book, “ Beast: Blood, Struggle and Dreams at the Heart of Mixed Martial Arts .” “On one level, cage fighting embodied much of what we’re taught is wrong: ‘It was aggressive, violent, an unrepentant celebration of what some would call regressive masculinity.