Mono was the playback medium for most record players, car radios, and transistor radios during the 1960s. Stereo playback systems had been available since the late 1950s, but the equipment and the albums mixed to play on them were expensive, and the music industry continued to manufacture mono albums and singles through the decade. Monophonic as a format would not be discontinued in both the United States and the United Kingdom until approximately 1969. As stated in the liner notes by Marcus, Moreover, the mixing of the album in mono was the chief priority of Dylan and his producers. Stereo was almost an afterthought. Producer Steve Berkowitz, who supervised the reissue of The Original Mono Recordings was told by Bob Johnston about the mixing of Blonde on Blonde: "We mixed that mono probably for three or four days, then I said, 'Oh shit, man, we gotta do stereo.' So me and a coupla guys put our hands on the board, we mixed that son of a bitch in about four hours!... So my point is, it took a long time to do the mono, and then it was, 'Oh, yeah, we gotta do stereo'." A similar box set compiling LP mono records by The Beatles had been released in 2009 to respectable sales results, awarded a platinum record by the RIAA. This may have been impetus for Sony to issue this set. Most of the albums were mastered from the original, first-generation master tapes. Only two albums were not: The Times They Are A-Changin' and Highway 61 Revisited. The original master tape for the former could not be found so a new master was mixed from the original three-track tape, using the original vinyl pressing as a guide. Highway 61 Revisited was mastered from a second-generation overseas copy of the mono mix. The genuine mono mix for John Wesley Harding was presumably released only in the U.S., whereas the original mono LP issued in the UK was apparently a fold-down of the stereo master. For The Original Mono Recordings box set, the producers used the genuine mono mix issued in the U.S. Initial purchase of the box allowed for free download of the non-album single "Positively Fourth Street" in mono, as well as the entire set in MP3. "Positively Fourth Street" was also included on the simultaneously released single-disc collection, The Best of the Original Mono Recordings. The original recordings were produced by John Hammond, Tom Wilson, and Bob Johnston.
Album listing
;Bob Dylan ;The Freewheelin' Bob Dylan All songs written by Bob Dylan, except where noted: ;The Times They Are a-Changin' All songs written by Bob Dylan. ;Another Side of Bob Dylan All songs written by Bob Dylan. ;Bringing It All Back Home ;Highway 61 Revisited ;Blonde on Blonde All songs written by Bob Dylan. ;John Wesley Harding All songs written by Bob Dylan.
