Beloved by millions, former teen idol Davy Jones died suddenly at the age of 66. This week's issue of PEOPLE looks back at the lead singer of The Monkees – a British pop star who made teenage girls swoon, entertained fans until the end, and whose fame changed music forever.

Performing at an Oklahoma casino on Feb. 17, Jones bounced across the stage, belting out the songs he helped make famous in the late 1960s as a member of the "Prefab Four," the Monkees. "He looked great and said he felt great too," recalls his sax player Aviva Maloney. "It was hilarious watching the lighting people try to keep up with him." That boundless energy made the Manchester-born singer's death of a heart attack on Feb. 29 in Florida all the more shocking. "It was very unexpected," his oldest daughter, Talia, 43, tells PEOPLE, adding that her father, a strict vegetarian and avid exerciser, "was the picture of health."

As the news spread, fans of the man known as the most crush-worthy Monkee harked back to their childhoods glued to the catchy tunes and crazy high jinks of the made-for-TV pop quartet (rounded out by guitarists Peter Tork and Michael Nesmith and drummer Micky Dolenz). The sitcom The Monkees ran for two seasons from 1966-68 and spawned four No. 1 albums in one year. Jones further cemented his legacy playing himself in a classic 1971 episode of The Brady Bunch in which Marcia (Maureen McCormick) lands him as her junior high prom headliner – and date. "Davy was a beautiful soul who spread love and goodness around the world," says McCormick.

Dolenz, who says Jones was "like a brother," recalls being wowed by the singer's charisma. "He was a classic entertainer, and that never changed…Davy was great to hang with. He was the go-to guy for having fun." Tork adds, "Davy could be incredibly insightful. Some of my best heart-to-heart moments have been with him… Nobody knows how awesomely smart he was. He was so gifted, he was practically a mutant." Says Talia: "He'd give you the shirt off his back. No matter how tired he was, he was gracious to everyone." Adding, "The life he had – it was like 10 lives! It's comforting to know dad had such a full one and touched so many."

Still, there were dark times after the Monkees disbanded in the early '70s. "I was depressed," Jones told PEOPLE in 1992. "I became a walking wild man, meeting two, three girls a day. I didn't know how to live." His first two marriages (which produced four daughters) ended in divorce. Jones had two DUIs near his farm in Beaverton, Pennsylvania, and lost the small percentage of Monkees royalties to bad investments. "I'm not as wealthy as some entertainers, but I work hard," he said. "A lot of people go days without having someone hug them or shake their hand. I get that all the time."

Jones, who wed actress-dancer Jessica Pacheco, 34, in 2009 had recently been focused on touring (he hit the road with Dolenz and Tork last year), writing a musical, and his beloved horses. The morning he died, the self-dubbed "Manchester Cowboy" had just been on a quick ride. Says Talia, "He went out doing what he loved." For now, those close to Jones are coming to grips with his loss. "He was a tremendous presence and a world-class performer," says Tork. "It's very hard to believe he's gone."

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