CHICAGO: For British author Mark Lewisohn, telling the story of the world's greatest rock band the way it deserves to be told will take time - a quarter-century, to be exact.

The noted Beatles scholar, 56, fell in love with the Fab Four as a child, and published his first Beatles-related reference work in 1986. His latest book, "Tune In," was published late last year.

The volume, which took 10 years to write, is the first in his planned "All These Years" biographical trilogy. It begins in 1845, when the Irish potato famine forced John Lennon's ancestors to migrate to Liverpool, and ends in December 1962, shortly after the group released its first single, "Love Me Do."

Lewisohn concedes that the length, 880 pages in the U.S. version and 1,728 in the unabridged British edition, may be daunting.

"Obviously, I want the book to be read by as many people as possible. But it's as long as it needs to be," Lewisohn told Reuters. "My interest is solely in learning as much as I can, to get the story as right as possible."

Reviewers have praised Lewisohn's deft balance of scholarly detail and gripping narrative. The author did not seek the blessing of Paul McCartney and Ringo Starr or the estates of Lennon and George Harrison for the unauthorised book.

"Access often comes with control, and it's crucially important that this is no whitewash," he explained.

Lewisohn hopes that Volume 2, which will break off the narrative around 1966, will be completed by 2020 and the third and final installment about seven years after that.

"With this project, it's not about 'I've got enough, I can stop now,'" he said. "It's 'If I don't turn over the next stone, I might miss the best thing of all.' So I will turn over every stone before I stop researching."

"Tune In" zeroes in on the youthful John, Paul, George and Ringo and their apprenticeship in the rock clubs of Liverpool and Hamburg, Germany.

Lewisohn hunted down early Beatles set lists and looked for patterns. He discovered that Harrison was an equal partner in the early days, at least in terms of sharing lead vocals onstage. The 1962 performances featured a "George vocal" on every third song, alternating with John and Paul, partly because manager Brian Epstein wanted to show off the group's versatility.

Lewisohn also demonstrates that, contrary to what some have said, Ringo was a talented musician, and Liverpool's most in-demand drummer.

"He was probably the only musician in Liverpool who had more stage experience than even John, Paul and George," he said. "Anyone who thinks he was an average Joe is actually insulting John, Paul and George with their choice" of recruiting Ringo.

Lewisohn feels he still has more to learn about the group.

"I certainly don't think that this is a book just for Beatles fans. This is a post-war history of our culture. These three books, when eventually the series is completed, will be something that I hope will stand for centuries to come."