By 1965, Buck Owens' star shone so brightly that even the Beatles -- the biggest band the world had ever known -- wanted to follow in his footsteps, covering his hit single "Act Naturally" on their Help! album, thereby kick-starting the golden era of country-rock in the late '60s. Thanks to the Beatles, many young rock & rollers now turned to Buck's Bakersfield sound as their template for what country music should be, reinvigorating rock & roll by adding what they learned from country, essentially reversing the equation Owens came up with at the start of the '60s, when he applied everything he learned from rock & roll to create the signature sound of that decade. Buck was grounded in '50s country but he had his head turned by rock & roll, eventually threading in the driving backbeat and electric guitars to his honky tonk background. This sound -- lean yet powerful as a locomotive, all fueled by the twin guitars and harmonies of Owens and his right-hand man, Don Rich -- became known as the Bakersfield sound, and it dominated country in the '60s, ruling the charts while creating scores of imitators and acolytes from Merle Haggard to Gram Parsons and Dwight Yoakam. The creation of that sound has never been as well documented as it is on Bear Family's 2008 set Act Naturally: The Buck Owens Recordings 1953-1964, which runs five discs and 159 tracks. Sometimes these big Bear Family sets are heavy on unreleased tracks, but that's not the case here; only 16 of the 159 cuts are previously unreleased (with 13 of them being alternates tacked onto the end of the set). This set may be skimpy on unreleased music, but most of Buck's recordings have been in circulation on CD, as Owens licensed his LPs to Sundazed for reissue (making him one of the few major country artists to have almost all his proper LPs appear on CD) and his pre-Capitol recordings were nearly all rounded up on Audium's 2001 set, Young Buck. So, the value of Act Naturally -- as it is with almost any Bear Family set -- is context, provided both by Rich Kienzle's excellent hardcover biography and the presentation of the music itself as the set systematically marches from his early recordings for Pep to his big hits for Capitol. What's startling about this is that those early singles do reveal Buck's roots so clearly, whether it's the debt "The House Down the Block" has to Hank Williams or how "Down on the Corner of Love" has the unmistakable midtempo gait of Buck's later "Above and Beyond," or how the rockabilly of "Hot Dog" and "Rhythm and Booze" -- a single released under the name Corky Jones -- hinted at the twanging Telecasters of his prime work. All these elements were in place from the start, but it took Buck a while to get there and Act Naturally follows every one of his footsteps, from his time backing Bud Hobbs on his MGM sessions to the first flowering of his signature sound on "Under Your Spell Again" in 1960 through Don Rich's switch from fiddle to electric guitar roughly a few months later. As the '60s rolled on, Owens didn't expand his Bakersfield sound so much as hone it, sanding off the edges and turning it into something cleanly efficient yet surprisingly versatile. Whether he was singing heartbreak ballads like "Crying Time" and skipping through neo-novelties like "I've Got a Tiger by the Tail" or singing tunes by Harlan Howard and Tommy Collins -- or turning in renditions of Red Simpson's "Close Up the Honky Tonks" and Terry Fell's "Truck Driving Man" that provided the blueprint for decades of country-rock to come -- he always sounded unmistakably like himself. He had a sound like no other and, with his expert ear, he built a songbook -- partially originals, partially expertly chosen covers -- that defined what modern country music was all about in the last 40 years of the 20th century. His impact is of course well known, but nowhere is it easier to appreciate than it is on this marvelous set.