Top Moments in Early Rock 'n' Roll            Whether you start the clock with Roy Brown's release of "Good Rockin' Tonight" in 1947 or with Elvis crossing the threshold of Sun Studio, rock 'n' roll is full of moments that illustrate how vital and dynamic the art form can be. Herewith, a timeline of some of the biggest:            Arthur "Big Boy" Crudup records "That's All Right," 1946. It's a sin that Crudup's song -- which Elvis Presley later recorded -- hasn't been properly acknowledged for launching rock 'n' roll. Arguably, it rocks harder than Presley's version. The rhythm section starts slowly and then takes off intensely, especially during an instrumental break that is pure rock 'n' roll. And Crudup's electric guitar drives the song as if there's no tomorrow as he sings of his love troubles (he quotes his father in the lyrics "Women will be the death of you"). The Mississippi-born Crudup released the song on RCA Records, and it was not a hit at the time, but the visceral excitement of the tune is unmistakable. (Elvis also recorded two other Crudup songs: "My Baby Left Me" and "So Glad You're Mine.") STEVE MORSE            Roy Brown records "Good Rockin' Tonight," 1947.Few pioneers are as underappreciated as Roy Brown, the New Orleans native who disappeared for long stretches because he was tired of record-label exploitation. But his "Good Rockin' Tonight" is an all-time rock classic. The words "Did you hear the news -- there's good rockin' tonight" caught rock's simple, hedonistic theme as well as anything from his era did. The song was later recorded by Elvis Presley (on his debut album) and by Jerry Lee Lewis and Ricky Nelson. Rhode Island's Roomful of Blues backed Brown at a memorable show at Cambridge's Jonathan Swift's club not long before Brown died in 1981 at age 56.S.M.            The Bo Diddley beat, 1955.Rock music is a series of brilliant guitar riffs -- Keith Richards's snarling guitar in "Satisfaction," Kurt Cobain's stuttering chords in "Smells Like Teen Spirit," Ritchie Blackmore's ominous opening to "Smoke on the Water." But the first great one belonged to Ellas Otha Bates McDaniel -- better known as Bo Diddley. So influential was his riff in his 1955 song "Bo Diddley" -- a rockin' locomotive beat filled with swagger and sex -- that it was borrowed by Buddy Holly ("Not Fade Away"), the Who ("Magic Bus"), and Bruce Springsteen ("She's the One"). Fun fact: During Diddley's first appearance on "The Ed Sullivan Show," Sullivan told Diddley to perform "Sixteen Tons," a hit for Tennessee Ernie Ford, instead of "Bo Diddley." Diddley agreed, but on the live broadcast, Diddley, much to Sullivan's chagrin, launched into his signature song. It was the last time Diddley appeared on the show. RENEE GRAHAM            Paul McCartney meets John Lennon, 1957. On a July afternoon in 1957, a 15-year-old Liverpudlian named Paul McCartney turned up at the Woolton Parish church social to catch a set by a local band called the Quarrymen, which featured another hometown musician, 17-year-old John Lennon. While a group of local teens milled about after the gig, McCartney picked up Lennon's battered acoustic guitar, turned it upside down, and played "Twenty Flight Rock" and "Be-Bop-A-Lula." Then he tuned it, which so impressed John he immediately invited Paul to join the band. JOAN ANDERMAN Back to the "Take Note" Main Page HIGHLY RECOMMENDED: CHECK ON THIS FINE PRINTING COMPANY: Promotional Products, Discount Labels, Post-it Notes, Rubber Stamps, etc.