In 1950, Bill Monroe had been on his own with the Bluegrass Boys for over 11 years and had been a Grand Ol Opry member for over ten. More importantly, he had had a successful run with Columbia Records and had left as his music had continued to develop for what he perceived to be a brighter, more lucrative future with Decca in 1950. As usual, Monroe's instinct was correct. The 103 selections compiled here are from Monroe's most fertile, creative period, many of the songs recorded during this era became his signature tracks, such as "Uncle Pen," "Raw Hide," "Get Down On Your Knees and Pray," "Little Georgia Rose," "On and On," "Roanoke," "The Little Girl and the Dreadful Snake," and "Kentucky Waltz." It was while at Decca that he introduced and recorded his original and trademark mandolin tuning, where instead of four pairs of strings tuned to the same pitches as a violin, he tuned several pair of strings to two different notes that added the otherworldly timbres to his "high lonesome" sound. In addition to Monroe's recording with the Bluegrass Boys, there are a number of sessions here that put Monroe in the solo spotlight with some of Nashville's hottest session cats, in an attempt by Decca to put Monroe's music in a more modern and mainstream country setting. What is most noteworthy about the period of recordings here, however -- besides the tracks themselves -- are the musicians who played with Monroe during those very fertile and adventurous years. Guitarists included none other than Jimmy Martin from 1950-1954, then Carter Stanley (briefly) before Eddie Mayfield, Jackie Phelps, and Doug Kershaw signed on. Bassists Ernie Newton and Bessie Lee Mauldin joined the band for the first time on these recordings, as did Buddy Killen briefly, and then Culley Holt. Fiddle players were plentiful and stunning during the '50s. Monroe certainly had the pick of the crop in Vassar Clements, Charley Cline, Bobby Hicks, and others. And banjo pickers, while still hard to come by in that three-finger style, were as fine as they came in Rudy Lyle, Don Stover, and Joe Stuart. There is the association here with legendary producer Owen Bradley as a sideman toward the end of the '50s, and the influence of Monroe on the music of the time, where his main competition -- Flatt & Scruggs, grudgingly (briefly) adopted Monroe's Nashville style to further their own careers -- and the spin-offs by Jimmy Martin and others began successful recording careers as well. The story the recordings themselves tell is one of ambition, vision, and restlessness. The songs come in strange batches: there are the numerous co-writes with Hank Williams, sometimes credited, other times willfully, but for no known reason obscured in their authorship. But Monroe's own writing was red-hot as well. His own compositions easily overshadow anything he covered during these years. Monroe was hunting ever deeper and wider for the elusive element that was the very grain of his style of music. He fought hard to keep it contemporary while not giving up anything in return. While it is not explained in the liner notes, his two Decca sessions with Nashville studio cats were perhaps a compromise Monroe himself made to keep the music of the Bluegrass Boys pure. These sessions, five and seven, included many fine songs -- "Sailor's Plea," "Highway of Sorrow," "My Carolina Sunshine Girl," "Peach Picking Time in Georgia" and others -- but only three of them were ever issued before this compilation; the rest, as fine as they were, were left in the bins and the liner notes in the book, as fine as they are, do not explain why the choices were made at the time to leave them on the shelf. In all, this is a stunning collection of Monroe's music at the beginning of his modern era; his first fully mature recordings that would prove so timeless and influential are here, and not on the Columbia recordings. The sound here is also, for the most part, pristine, and never less than very good, with great balancing and equalization. As is customary with Bear Family, the book is chock-full of information and complete session notes, making it an indispensable package, and, along with its companion set, from 1959-1969, the only recordings by Monroe anybody would ever need to really take in his contribution.