In 1949, 7-inch 45 rpm records were introduced into the marketplace as an alternative to the more fragile 78-rpm shellac records. And while 45s could typically only hold one song per side — hence their nickname, “singles” — their affordability and availability on neighborhood jukeboxes made them attractive to teenagers, a previously untapped demographic.

A new market for music was born, and in its wake, new forms of music. If it wasn’t for the 45, it’s doubtful that R&B would have crossed over into the mainstream pop charts and given birth to rock ‘n’ roll.

Over time, artists began concentrating less on creating hit singles and more on creating cohesive albums, making 12-inch LPs more popular than the 45. And as the demand for more portable music increased, other platforms were introduced — 4-track tapes, 8-tracks, cassettes — each diminishing the demand for vinyl.

By 1990, vinyl had been replaced by CDs; 10 years after that, CD sales began a rapid decline in favor of digital downloads. Buying a physical product from a record store was becoming akin to purchasing a new horn for a Victrola.

Then came Record Store Day. The brainchild of Maine-based Bull Moose Music marketing head Chris Brown, the annual event not only put the spotlight back on record stores, it brought back vinyl both as a source of high-quality sound and as limited-edition collectors’ items. On Saturday, more than 300 vinyl releases by everyone from Little Richard to The Black Keys will be issued exclusively on Record Store Day.

And what’s the format that is being touted as having the best sound quality? The 45. Several artists, including Fleetwood Mac and Garbage, are issuing new or classic recordings on 45-rpm vinyl for Record Store Day because audiophiles say that more revolutions per minute result in better sound quality.

The circle is now complete. A new revolution has begun. And before you get sick of my bad puns and stop reading, here’s a list of some of the most collectible 45s of all time (prices reflect copies in mint condition and are approximate based on vinyl collecting websites):

Frank Wilson, “Do I Love You (Indeed I Do)” (Soul, 1965, promotional copy, only two copies known to exist): $30,000

Sex Pistols, “God Save the Queen”/”No Feeling” (A&M, 1977, UK version with mailer, pulled before official release): $22,000

The Quarrymen, “That’ll Be the Day”/”In Spite of All the Danger” (private 1981 reproduction, only 25 copies known to exist): $18,000

Queen, “Bohemian Rhapsody”/”I’m in Love with My Car” (EMI, 1978, on blue vinyl, issued during in-house company event): $9,000

The Misfits, “Horror Business” (Plan 9, 1979, promotional copy): $8,000

The Beatles, “Love Me Do”/”P.S. I Love You” (Parlophone, 1962, promotional copy): $5,000

Of course, most 45s are worth a lot less than these, so don’t think you’ll get rich by buying up every single in sight on Record Store Day. Do buy them because the sound quality is superb, they’re exclusive, and they’re cool.

And because you’ll be supporting your local record store instead of some faceless conglomerate selling bits of data.

Deputy Managing Editor Rod Harmon may be contacted at 791-6450 or at:

[email protected]

Twitter: RHarmonPPH