As Gibson Les Paul sales began to wane in the late 1950s, Gibson president Ted McCarty decided to do a complete re-design of that now-iconic body shape. First released in 1961, the new Les Paul / SG was radically different than anything that had come before it. The hand carved, arched maple tops of the previous models were gone, leaving a much lighter and thinner all-mahogany body. The side edges of the body were contoured and beveled for increased player comfort, and the body was reshaped into a slightly asymmetrical double cutaway design with distinctive "points" at the end of the horns. Additionally, the neck was re-shaped as well, and it was much thinner, with a practically nonexistent "heel" -- Gibson advertised it as "the fastest neck in the world" at the time.
After the first year or two of production of the new "Les Paul", and at his request, the Les Paul name was officially dropped, and although his name still appeared on the truss rod covers of some of the guitars for a year or two, the model became known as the SG, which stands for "solid guitar." Some speculate that Les wanted out of the endorsement deal due to a divorce he was involved in at the time, while other accounts say Les just wasn't crazy about the new design. Whatever the reason, it didn't matter in the end, because lots of other musicians liked the new model, and it was an immediate success -- far eclipsing the sales of 1950s era Les Pauls. In fact, the SG Standard is the best-selling Gibson model of all time.
When it was first released, the SG Standard came equipped with a 24.75" scale neck with white trapezoid inlays, a tune-o-matic bridge, two double-coil humbucking pickups, two volume and two tone controls, and a three-way pickup selector switch -- just as it does today. The neck / body joint has a much smaller "heel" on an SG than on a Les Paul, and the neck connects three frets further down the neck at the 19th, as opposed to the 16th fret, giving the SG an advantage in terms of the player's access to the upper frets. This comes at a bit of a price though, since the lighter body and "longer" neck results in a somewhat neck-heavy balance to the guitar when it is worn on a strap.
Although it's a versatile guitar, with excellent warmth and sustain, the SG has probably found its greatest acceptance with rock and metal guitarists. Some SG Standard players of note include Angus Young (AC/DC), Tony Iommi (Black Sabbath), Robbie Krieger (The Doors), Derek Trucks (Allman Brothers Band), Daron Malakian (System Of A Down), Duane Allman, Eric Clapton, Buck Dharma (Blue Oyster Cult), George Harrison (The Beatles -- primarily during the Rubber Soul / Revolver era), Pete Ham (Badfinger -- who used George Harrison's SG, which he received as a gift from Harrison), Ian MacKaye (Fugazi), Todd Rundgren, and Jeff Tweedy (Wilco).