Back to the basement to finish a project Bob Dylan began in 1967

How fertile was the “Basement Tapes” period in 1967 when Bob Dylan holed up in upstate New York, away from fan and media scrutiny, writing and recording song after song after song with the group soon to be known as the Band?

Their months-long collaboration yielded about 100 songs, captured on relatively crude two-track tape recordings now being issued in complete form for the first time. Dylan also wrote dozens of other sets of lyrics that he never got around to finishing, a chunk of which are newly completed in “Lost on the River: The New Basement Tapes,” a related project for which producer T Bone Burnett assembled an ad hoc band to compose music for those long-shelved lyrics.

The group consists of Elvis Costello, Marcus Mumford, Jim James of My Morning Jacket, the Carolina Chocolate Drops’ Rhiannon Giddens and Dawes singer, songwriter and guitarist Taylor Goldsmith. Last spring, they gathered at Capitol Records in Hollywood for two intensive weeks, during which they wrote and recorded more than 50 tracks.

The main goal was to finish what Dylan had left undone — as has been done in recent years with unfinished songs left behind by Hank Williams (“The Lost Notebooks of Hank Williams”) and Woody Guthrie (in several projects authorized by Guthrie’s daughter and estate manager, Nora).

The big difference with the Dylan project, as Costello noted with a laugh, versus those with Williams and Guthrie, “They weren’t around — they couldn’t say, ‘No! You can’t do that!’”

The “New Basement Tapes” ensemble aspired to channel a similar esprit de corps that’s evident in the recordings Dylan and the Band made 47 years ago. That played out in long days of communal writing sessions, followed quickly and sometimes simultaneously with recording sessions, editing, mixing, rewriting and re-recording.

In a couple of cases, each of the core musicians came up with his or her own musical setting for a given set of lyrics. In many cases, there are two and three versions, and executive producer Burnett says he hopes to release all of them one day, for music fans and historians to see how one artist’s lyrics could affect others, sometimes in drastically different ways, sometimes in uncannily similar ways.

For now, the focus is on the 15-song standard edition album and a 20-song deluxe edition, both due Nov. 11, and an accompanying documentary by filmmaker Sam Jones, “Lost Songs: The Basement Tapes Continued,” set to premiere Nov. 21 on Showtime.

“For me,” Jones said, “it’s fascinating to stand by and watch the creative process. Everyone approached it differently. Some came in with very worked-out demos, like Jim, whereas Marcus thought the spirit of the project was to come in and do it on the fly. And both results work great…. To literally watch Marcus run away for five minutes and come up with an idea for a song, come back and show it to the others and have it be fleshed out on the [recording studio] floor in 30 minutes — to see that creative process just blooming before your eyes was remarkable.”

Burnett, whose working relationship with Dylan goes back nearly 40 years to when Dylan recruited the Texas musician to be part of his Rolling Thunder Revue, said of the songs being newly brought to life: “If you look at the words on the page, you see they’re certainly not poetry. I can see why Bob has resisted being called a poet all this time. But once you sing them, they become lyrics. And as soon as you sing them, you realize, ‘No, these are not B-level lyrics, they’re just as affecting as any of the others he wrote during this time.’”

Twitter: @RandyLewis2