Forty years ago, Elvis Presley launched what became the second phase of his phenomenal career with a landmark television special which served to remind the general public of what a musical force he had been -- and was yet to become.

Officially titled "Elvis," the one-hour special is commonly referred to as 'The '68 Comeback Special,' because of the dramatically positive impact it had on Elvis' then-sagging image. On August 5, Sony BMG marks the 40th anniversary with the release of a four-CD set, 'Elvis: The Complete '68 Comeback Special,' featuring all the music he recorded in multiple shows and rehearsals for the program, including 20 previously unreleased tracks.

Aired Dec. 4, 1968, the special mixed splashy production numbers with an intimate live performance in which the King, dressed in black leather, delivered some of his earlier hits in an informal setting -- a Burbank sound studio --- for a wildly enthusiastic crowd. The show generated a couple of new hits -- 'If I Can Dream' and the Mac Davis-penned 'Memories' -- and included live versions of the Elvis classics 'Jailhouse Rock,' 'Heartbreak Hotel,' 'Love Me Tender' and 'All Shook Up.' In addition to a total of 103 songs, including 'That's All Right,' 'Blue Christmas,' 'Don't Be Cruel,' 'Guitar Man' and 'Blue Suede Shoes,' the package features a 32-page booklet of liner notes and photos.