Reputed mob boss John Gotti was described as ``God's gift to the underworld'' in tapes secretly recorded by law enforcement agents and played Wednesday to jurors at his assault and conspiracy trial. Prosecutors say Gotti, 49, became boss of the Gambino crime family, largest of New York's five Mafia factions, in December 1985 after then-boss Paul Castellano was gunned down in front of a steak house. Transcripts of the tapes, which were released to the news media, show Gotti concerned about keeping underlings, including lifelong friends, in their place. At least once on the tapes, Gotti uses the term ``Cosa Nostra' when he is apparently telling an unidentified man that mob soldiers should not address him directly on business matters but should go through their ``capos,'' or captains. The tapes also indicate a relationship with the Westies, a vicious Irish-American gang that operates on Manhattan's West Side. The Westies are a key factor in Gotti's trial with associate Anthony Guerrieri, 60, on charges of assault and conspiracy in the 1986 revenge shooting of John F. O'Connor, former vice president of a Carpenters Union local. Gotti is accused of commissioning the Westies to shoot and wound O'Connor because the union leader had thugs trash a restaurant owned by Gotti associate Philip ``Philly'' Modica. The transcripts show at least one mention by Gotti of the restaurant and several comments on the Westies. At one point Gotti says ``...they're doing something for me them Irish guys...,'' but does not say what. At another point, Gotti refers to James Coonan as ``my friend'' who is ``the leader of the West Side gang, Irish guys.'' He also says, ``He's on the payroll, and he gets it legitimately ...'' The tapes were introduced by Edward Wright, an investigator with the state's Organized Crime Task Force. Wright said the alleged mobsters, suspecting they might be under surveillance, turned on hair dryers, flushed toilets, whispered and used other means to try to make conversations inaudible. The tapes were made from listening devices placed in Gotti's hangout in the borough of Qeens and monitored by police between June 19, 1985, and Feb. 26, 1986. More than 1,000 cassettes were recorded, prosecutors say. One 1986 tape shows Gotti in a telephone conversation quoting someone who praised him: ``When they say God's gift to the underworld, you are it. ``He speaks with his heart,'' Gotti said on the telephone. ``He means it. I tell ya something, I love the guy.'' On another tape, Gotti expressed annoyance with lifelong friend Angelo Ruggiero for his familiarity during business hours. ``I told Ange, `You gotta forget them liberties you take. Take `em when we're alone,''' Gotti said. Gotti apparently had just made Ruggiero a ``caporegime,'' or crew captain, according to the tape transcripts, and was not satisfied that his friend was acting like a leader. Ruggiero, a defendant in the O'Connor case with Gotti, died of natural causes last month.