This box set mostly consists of never-before-released songs recorded during the sessions for his many albums, but also includes a number of single B-sides, as well as demos and alternate versions of already-released material.

[5] Springsteen, engineer Chuck Plotkin and manager Jon Landau had considered releasing these songs in their current rough-mix form, going as far as mastering them in a test-run to get an idea of what they would sound like, but following a listening session in June, it was decided to mix them properly from the original multi-track tapes.

Around this time, Sony Music was alerted that the project was in-progress, and they created their own timetable for promotion and release with a September 10 deadline for the final submission of the master tapes.

Springsteen called in then-former bandmates Danny Federici and Clarence Clemons, along with original drummer Vini Lopez, to fill in the missing pieces.

Additionally, they began scheduling mix sessions across three different studios as the engineers' availability would be limited due to work with other clients.

[5] On a typical day in August, when all three engineers were working simultaneously, Panunzio and Thacker would generally set up a mix during the evening, returning the next morning to finish.

Plotkin would be present, adding his input, and he would also have his mixes played back in real time on a receiving unit set up in Springsteen's living room at the compound.

[5] Even though the original intention was to cover material from all aspects of Springsteen's career, acoustic demos from 1972 (such as "Arabian Nights", "Jazz Musician", "Ballad of the Self-Loading Pistol", and "Visitation at Fort Horn") were not available for release, due to ongoing court proceedings surrounding the songs (concerning the attempted release of these songs by a different, European based label in 1993).

As a result of the project, Sony Music also created its own archive database, making extensive use of Scott's cataloging efforts over the previous decade.

[5] In an interview with Rolling Stone in September 2020, Springsteen suggested that a follow-up box-set of unreleased material is in the works: "There's a lot of really good music left.