In the late ’70s, Bruce Springsteen’s songwriting, sound and overall artistic temperament underwent a radical transformation. It began with Darkness on the Edge of Town. The unabashed romance of Born to Run still fuels a good deal of the music, but at the same time, weariness and restlessness creep into several tunes, notably “Factory” and the foreboding “Badlands.” Structurally speaking, the music is tougher and stripped down. There’s no strings and less grandeur, a moody atmosphere and more guitar.

With the E Street Band on the road, Springsteen carved out time to begin work on a massive batch of songs that would further intensify the light/dark dualism underpinning Darkness. The inspiration flowed fast and hard. An album titled The Ties That Bind was slated for release in 1979 but was scrapped because Springsteen couldn’t shut off his creativity — he just kept on churning out amazing material. Eventually, the project ballooned into a double album: the 1980 masterpiece The River.

The Ties That Bind: The River Collection sheds much-needed light on what is arguably the most prolific stretch of Springsteen’s career. In addition to a newly remastered The River, the box set boasts a reconstructed track-list for the aborted full-length and nearly a dozen outtakes that languished in the vaults for years.

Comparing the original “Stolen Car” intended for The Ties That Bind with the later version that made it on to The River demonstrates just how swiftly Springsteen’s outlook — personally and politically — was darkening. Where the former opens with bold keys and a dramatic reading from Springsteen, the latter finds the singer withdrawing into a haze of reverb suffused with loneliness and fatigue. Recorded in early 1980, toward the tail end of The River sessions, the stunning outtake “Stray Bullet” is even more ominous. It closes with the singer hypnotically chanting, “But you’ll never wash away the sound — of the stray bullet that shot my baby down.” This is gloomy stuff and definitely sets Springsteen down the path toward the unremitting dread of 1982’s Nebraska.

But again, The River era is marked by an intense interplay between light and darkness. For every “Stray Bullet,” there’s an outtake like “Meet Me in the City,” a zippy rocker featuring newly recorded vocals from Springsteen (who sounds absolutely ageless, it has to be noted). “Party Lights” is yet another vintage slice of hard-rocking Boss. Having made the bootleg rounds for years as a sparsely arranged home demo, this previously unreleased studio version boasts a driving blend of Byrds-inspired jangle and walloping drums. Had Springsteen penned the tune back in the mid ’70s, it surely would’ve been encased in a Phil Spector-inspired wall of sound. But by the end of the decade, he was far more interested in compact arrangements that showcased the E Street Band’s mix of rockabilly twang and punchy power pop. It’s a sound that would exert a massive influence over the roots-rock movement of the ’80s.

Much like 2010’s The Promise, another archival set meticulously chronicling Springsteen’s early years, The Ties That Bind box set demands considerable time investment from listeners. But it’s an absolutely essential exploration for anybody who cares deeply about rock history and in particular the evolution of one of the music’s greatest voices.