TUNE IN: THE BEATLES: All These Years, Vol. 1. By Mark Lewisohn. Crown Archetype. 944 pages. $40.

On a Sunday evening 50 years ago today, I was among 73 million Americans watching TV when Ed Sullivan said, "Ladies and gentlemen, the Beatles!" These were the words that triggered a pop-culture seismic event, the magnitude of which had never before been witnessed.

To American teenagers, the Beatles were new, but the lads from Liverpool (the core of John Lennon, Paul McCartney and George Harrison) had traveled a long and winding road to reach the Sullivan stage, having been together for more than six years. They only stayed together for another six years, but that was enough to forever change a generation and its culture.

The Beatles' enduring popularity is remarkable. Baby Boomers embraced the Fab Four, but so have their children and grandchildren. Pricey rereleases of Beatles recordings in box sets have sold out and gone platinum. And more books about the Beatles have been published than about any other rock band.

Now comes "Tune In." Mark Lewisohn, author of the well-regarded books, "The Complete Beatles Chronicles" and "The Complete Beatles Recording Sessions" (for which he was the only person to be commissioned by EMI to listen to all of the Beatles' original session tapes), is generally considered the leading authority on the Beatles. His three-volume history, of which this is the first book, has been highly anticipated. And it does not disappoint.

Lewisohn's 900-plus page behemoth - and this is the abridged version; there is a 1,728 page, two-volume bigger sibling currently available in the U.K. - covers the years through 1962, when the Beatles reached the verge of stardom.

The barebones narrative is familiar to most fans: Lennon forms a band, the Quarrymen. McCartney sees them at a church fete and is introduced to by their mutual friend, Ivan Vaughan. After hearing him sing and play, Lennon invites McCartney to join the group. He introduces his guitarist-friend, Harrison, and voila, the Beatles are born. (Harrison eventually invites Ringo Starr to join, but that is much later.) The band struggles along until they go to Hamburg, where they hone their craft fueled by Dexedrine and Preludin, performing virtually nonstop, "the equivalent of three hours every night for a full year." They return to Liverpool, where they develop a devoted following. Brian Epstein hears them at the Cavern club, is gobsmacked by their energy and charisma (only slightly less so by their music), and becomes their manager. They audition for producer George Martin of EMI and sign a record contract.

Although you might believe that everything that could be written about the Beatles has already been written, Lewisohn proves otherwise. The devil is in the details. Through passionate and thorough research (he moved to Liverpool for six months and made trips to Hamburg and the U.S.), original interviews, and access to new material, he creates a vivid picture of the formative days of the band. Lewisohn received a wealth of new material from the late Neil Aspinall, who began as the Beatles roadie and close mate, and later became their manager and an executive at Apple Corps. Among the most valuable resources include Epstein's diaries, transcripts and business records.

Lewisohn's quotes from those who followed the Beatles in their Liverpool days at the Cavern - old girlfriends, family and various peripheral characters - make each of the Beatles come alive. And the dynamics between John, Paul and George emerge clearly in the book. John, the eldest, is looked up to by Paul and George, who crave his attention. Though the term "bully" isn't used, we understand that John was one. He hit young women, made fun of the disabled and turned his sarcasm on anyone around him.

Paul, the middle one, attempts to keep George aware of his junior position. George constantly tries to assert himself. Despite the tensions, the three men became so close they virtually developed an exclusive language to use with one another.

The introduction of Stuart Sutcliffe, the brilliant art student and John's friend, into the group prior to their time in Hamburg complicates the dynamic. Paul's obvious jealousy of Sutcliffe led him to treat him badly and created tensions. Lewisohn also shares details about Ringo: his sickly childhood and parallel path with another band, Rory Storm and the Hurricanes. It becomes clear that the Beatles' original percussionist, Pete Best, was neither a particularly good drummer nor one of the boys, making his departure, and Ringo's arrival, inevitable.

Much, too, is written about Epstein and Martin, both integral to the Beatles' story. And Lewisohn provides lots of revelations and interesting tidbits. His retelling of the scene between Lennon's father and mother, when they were deciding with whom their son would live, is at odds with John's perhaps apocryphal story.

Klaus Voorman, who was a graphic artist when he met the Beatles in Hamburg (he designed the famous cover of "Revolver," among other albums), begged to become the Beatles' new bassist when Stuart Sutcliffe left the group, but was rebuffed because Paul had already bought his famous Hofner violin-shaped bass.

The story of how the Beatles got their recording contract differs significantly from previous tellings. Epstein appealed to EMI's publishing group, telling executives they could publish Lennon-McCartney songs if they gave the group a recording contract. Martin initially resisted recording the band, but EMI's managing director demanded it.

As in any epic, one can find a few flaws. The author gives more than ample space to the death of Lennon's mother and the effect it had on John, yet there's only a small paragraph about McCartney's mother dying when he was just 14, an event that had a huge effect on the family. But there is little to criticize and much to hail, such as Lewisohn's encyclopedic knowledge of the Beatles and their works, including when songs were first written and often where songs were performed.

Among the 24 pages of photos are some gems. And the 75 pages of endnotes include much arcane minutiae, such as: "Like Penny Lane, Mathew Street is named after a slave-ship captain."

It has been nine years since publication of Bob Spitz's excellent book, "The Beatles: The Biography." Hunter Davies wrote the first and only biography authorized by the Beatles in 1968 (revised twice since, the last time in 1986). But Lewisohn's work, should he complete the final two volumes, will no doubt stand as an unparalleled monument.

Reviewer Michael Nelson is a writer and editor in Charleston, and a Beatles fan.