The 56-year-old Irishman's efforts have been rewarded with a whole host of landmarks including a record 12 Epsom Derbies and in 2017 the most Group/Grade One wins in a season.Another one can come his way this week as he needs just four winners to become the first trainer to bring up the century mark at Royal Ascot. One of six children he caught the racing bug off his late father Denis, who was primarily a farmer but trained a few horses in County Wexford in the southeast of Ireland.After a successful start to training jump horses, O'Brien caught the eye of John Magnier.The owner of the powerful Coolmore Stud operation in County Tipperary chose him in 1996 as the successor to his namesake and Magnier's father-in-law Vincent O'Brien, arguably the greatest trainer of the 20th century.O'Brien, who is a non-smoker and abstains from alcohol, has more than rewarded his judgement.His handling of horses is impeccable but so too is his management style with the stable staff which has ensured a happy ship over the last three decades.Indeed he rarely misses a chance when interviewed after another big win to immediately launch into reeling off a host of staff connected with the winner. Legendary Manchester United manager Alex Ferguson, never one to dole out praise freely, saw O'Brien up close when he enjoyed great success with Rock of Gibraltar which he part-owned. "When I go round Aidan's stables and I see him addressing every member of staff by name it takes me back to the time when I was in charge of Aberdeen," Ferguson told AFP at Longchamp racecourse in 2002."It's the same sort of tight knit operation."'Find holidays stressful'This begins at the top with his family -- mum Stella he rings immediately after every major race win and his wife Anne-Marie is an integral part of the team."There is no doubt Anne-Marie changed my whole life," he told The Irish Times."I couldn't believe the first day she spoke to me and then she came back and spoke to me again, I couldn't believe it."Their sons Joseph and Donnacha, along with daughters Sarah and Anastasia, have unsurprisingly fallen in love with the sport.Indeed both the boys have forged successful training careers after impressive stints as jockeys -- in 2012 Joseph, then just 19, and Aidan made history as the first father/son trainer/jockey combination to win the Epsom Derby when Camelot prevailed.