e did the wrong thing for the right reason. He became a cop because he wanted to defend his city after terrorists attacked the World TradeCenter. A bleeding-heart, tree-hugging,bike-riding liberal in a Kevlar vest. Some things just don’t mix.

With a glass jaw, an over-trusting nature and a deep fear of confrontation, Paul Bacon, a young, hip, scholarly left-winger, joined the NYPD in 2001 and lived to write about it in “Bad Cop: New York’s Least Likely Police Officer Tells All.” Unlike most cop books, “Bad Cop”doesn’t celebrate the heroism of a police career. Instead, it hilariously chronicles three years in the life of a nice guy who wanted to do the right thing but who personified the suspicions of fellow officers that a liberal in uniform could prove a danger to himself and others.

Bacon readily admits that before coming on the job he had “never met a cop who wasn’t writing me a ticket” and that all he knew about police culture he had learned from college sociology courses “and the televised comments of Rev. Al Sharpton.” His honesty about himself and his misconceptions about the glamorous life of an NYPD cop are riotously funny and deadly accurate. He describes Mayor Bloomberg’s appearance at his swearing-in ceremony this way:

“Bob Denver could have sauntered onstage in his Gilligan hat and made a more commanding entrance.” It gave him the impression that “City Hall was run by kindly old men.”

The next speaker, PBA president Pat Lynch, on the other hand, emerged as “a barrel-chested man with a pinstripe suit and a slicked-backed Gordon Gecko hairdo” who had some real news for them.

Lynch, he writes, “leveled one indictment after another against the department’s top brass, painting them as more dangerous to cops than all the city’s gangs put together.” Lynch described how the public didn’t pay attention to police work until we made a mistake...“Then, everything we did in the heat of the moment would be judged by people with nothing but time on their hands and no idea of the pressures we faced.”

Lynch, he continues, delivered the sobering news that these recruits “have never been closer to getting arrested than you are at this very moment” and that the PBA would be there to defend them through it all. For a humorous book, there’s a lot of truth there and we’re only up to page 25!

“Bad Cop” takes us through the trials and tribulations of a recruit issuing his first summons, doing car stops and encountering a ripe DOA near the end of a tour when he was already exhausted from working in a short-staffed precinct. He is confused by being on the opposite side of political protest barriers, trying to keep peace among people he agreed with, or at least used to. He wonders how he ever took himself so seriously during his protesting days.

But, sandwiched between anecdotes and antics, the author explores serious issues like summons and arrests “non-quota quotas” and the pressure on young cops to downgrade crimes, all seen through the eyes of an inexperienced idealist. In about 30 months, Bacon goes from gung-ho cop to a self-described “hairbag” doing his best to shit-can jobs. The stress and exhaustion of policing took a physical and mental toll on him. But he had the courage to admit that he shouldn’t be a cop. The incident that finally made him realize this is just too funny to give up here. Read the book and I promise you’ll laugh.

The good news for him: There is life after the NYPD. He now lives in Hawaii, where he teaches scuba diving — which was his true ambition all along. And after having rescued a drowning scuba student, Paul Bacon finally knows what it feels like to be a real cop.

“Bad Cop” hits the local bookshelves on March 18th and is available for pre-order on Amazon.com now.