When it comes to the list of bands that could conceivably overcome the twin hurdles of personal animosity and encroaching decrepitude to reunite in 2015, there is only one act that would be a) turning 50 and b) a big enough deal to qualify as a cultural event as well as a musical one.

Only half the Beatles are left, so they’re out. The Stones and the Who have never been away long enough to qualify.

It’s a stretch, but a case could be made for the Kinks had they not already blown the chance to celebrate their 50th this year, though they could no doubt locate a round-numbered anniversary of some sort in 2015 if the Davies brothers ever decide to choose avarice over disaffection.

That leaves the half-century club with one notable member: the Grateful Dead.

Coincidentally, next year will also mark the 20th anniversary of Jerry Garcia’s death and co-founder Ron “Pigpen” McKernan is long gone, but a stubbornly enduring four-member core remains to legitimize a reunion.

Guitarist/vocalist Bob Weir, bassist Phil Lesh, drummer Bill Kreutzmann and percussion wiz Mickey Hart are all still standing, despite battling a variety of ailments. And their ages — Weir is the youngest at 67, Lesh the oldest at 74 — lend the scenario an undeniable it’s-now-or-never element.

While all have been members of post-Garcia offshoots the Other Ones and the Dead, regrouping under the original moniker would signal something else entirely.

Among the evidence being cited for an imminent return:

The sudden dissolution this month of Further, the band formed by Weir and Lesh, who signed off their note to fans with the conveniently cryptic, “We’ll all be keeping very busy over the foreseeable future …”

Weir’s biographer expects the reunion to involve headlining one or two festivals and playing some West and East coast residencies, largely to get around “exorbitant insurance policies” for a big tour

Weir has been especially vocal about his desire to surmount any lingering personal issues. “If there are hatchets to be buried,” he told Rolling Stone in January, “then let’s get to work.”

The online fan community Terrapinnation.net cites this passage from the band’s 2014 almanac: “And by the time we meet again in this virtual neighborhood (sic), we will have observed the 50th Anniversary of the Grateful Dead. In fact, we are already well into the fiftieth year, since the band’s beginning, which most Deadologists carbon-date as having occurred on June 18th, 1965 — Phil Lesh’s first show with the Warlocks at a dive called Frenchy’s in Hayward, CA, thus completing the core lineup. We do not yet know the exact form the commemoration of this auspicious anniversary will take, but this remarkable journey is something worth celebrating, and celebrate we will.”

Buttressing all of the circumstantial evidence is the kind of prestige tie-in that all artistic events demand: an authorized documentary that counts as an executive producer Martin Scorsese, who once helped transform another musical event, The Last Waltz, into a cultural one, as well.

Still not convinced? Consider this: the band is already selling a 50th anniversary calendar.

VINYL COUNTDOWN: The week before Christmas will bring three posthumous releases by Nick Drake back to vinyl in Canada.

Made to Love Magic is notable for a very early solo version of “River Man”; A Treasury, which concludes with the brief, previously unreleased instrumental “Plaisir d’Amour”; and Family Tree, which gathers together more than an hour’s worth of home recordings that have surfaced on a variety of bootlegs over the years. Among those tracks are songs featuring Nick’s mother, Molly, and sister, Gabrielle. All three are out Dec. 16.

Also due out here in December: a box set that brings back to vinyl all eight studio albums by Rainbow, the band Ritchie Blackmore formed after leaving Deep Purple. The Polydor Years is scheduled for a Dec. 2 release.

A week later, the most infamous Sex Pistols bootleg, Spunk, resurfaces on vinyl for the first time since the collection of demos and early versions of songs that would wind up on Never Mind the Bollocks was pressed in limited quantities in 2006.

Meanwhile, a mere two days before Christmas, Daft Punk’s Grammy-winning Alive 2007 will belatedly arrive on vinyl, seven years after its release in CD and digital form.

For those select few who are not worried about January’s credit card statements, the set will come in a limited-edition box containing two white LPs plus an extra disc of encores, a separate silver-vinyl version of the band’s first live album, Alive 1997, a book and even a turntable slipmat.

For those of us who are worried about January’s credit card statements, both live albums will also be released separately, as a two-LP package for 2007 and a single 45-minute record for 1997.

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Finally, this month will see one of the genuine masterworks of the punk era return to vinyl, where it has belonged all along. Patti Smith’s still-influential debut, Horses, re-emerges on that format on Nov. 18, almost exactly 39 years since its original release.

Smith has announced tentative plans for a tour around the album’s 40th anniversary next year.