Over the course of his career, Mark Lewisohn has worked for EMI, MPL Communications and Apple Corps, and has written many reference books about the Beatles. He has been referred to as the world's leading authority on the subject, renowned for his meticulous research and integrity.
In 1986, Lewisohn's book The Beatles Live! was published. This featured a complete history of all the Beatles' live performances, in a format which Lewisohn would follow for his subsequent books. After being invited by EMI to listen to all of The Beatles' original session tapes, Lewisohn wrote The Complete Beatles Recording Sessions: The Official Story of the Abbey Road Years, which was published in 1988. The book was in the form of a diary, detailing every recording session The Beatles had at Abbey Road Studios chronologically. It included details such as who played on each track and how many takes were recorded in each session. The book featured an introductory interview by Paul McCartney.
Lewisohn's next book, The Beatles: 25 Years In The Life, was published in 1988 and included information on what each individual member of the band was doing on any particular day between 1962 and 1987. This book was republished as The Beatles Day by Day in 1990. The Complete Beatles Chronicle was published in 1992 and went one step further, detailing the band's entire career in the studio, on stage, and on radio, television, film and video.
Lewisohn's next book was The Beatles London, which he co-authored with Piet Schreuders and Adam Smith, published in 1994. This is essentially a guide book to all the Beatles-related locations in London, including Abbey Road and the London Palladium, featuring maps and photographs of the band at the locations mentioned. A revised version of the book was published in early 2008.
As well as writing his own books, Lewisohn has written forewords to such books as Recording The Beatles by Brian Kehew and Kevin Ryan, Beatles Gear by Andy Babiuk and the German book Komm, Gib Mir Deine Hand by Thorsten Knublauch and Axel Korinth. He has also contributed to In My Life: Lennon Remembered, a book to accompany the 10-part BBC radio series about John Lennon, and edited McCartney's book Wingspan, after working for a long time as editor and writer for McCartney's (now ceased) fanzine Club Sandwich. This led to him being invited by the former Beatle to write the liner notes for several of his albums, namely Flaming Pie, Band on the Run: 25th Anniversary Edition and Wingspan: Hits and History. He also wrote the liner notes for the retrospective six-CD box set Produced by George Martin – 50 Years in Recording, and The Beatles' albums 1 and The Capitol Albums, Volume 1. He was heavily involved in The Beatles Anthology project.[dead link]
According to Daniel Finkelstein, writing in The Times in 2014, Lewisohn was responsible for identifying comedian Jasper Carrott as the source in 1983, of the famous remark, "Ringo isn't the best drummer in the world. He isn't even the best drummer in the Beatles." This observation has generally been attributed to John Lennon, but Lewisohn had been doubtful because he could find no record of his having said it and thought it was out of character for Lennon to say something that he did not actually believe.
In 2005, Lewisohn announced that he had started work on a three-volume Beatles biography. He was quoted as saying of the work:
The Beatles story has been told very often but, in my view, rarely very well. I'm writing a wide-ranging history and my aim is true: to explore and comprehend what happened in and around the Beatles, and to write it even-handedly, without fear or favour, bias or agenda. A rock and roll group came out of Liverpool and shaped the last half of the 20th century the world over, and their music transcends changing times. The whole extraordinary story needs to be fully recorded and it needs to be done now, while first-hand witnesses are still with us.[dead link]
Volume 1 was published in October 2013, entitled The Beatles: All These Years, Volume One – Tune In. Lewisohn was quoted as saying "It took longer to research and write than I could ever have anticipated". In an interview published on 28 December 2013, Lewisohn estimated that the second volume would be published in 2020 and the final volume in 2028 ("about the time he turns 70").
Although The Beatles is Lewisohn's area of particular expertise, he has also written on a variety of other subjects. One of his best-known works is an encyclopaedia of comedy on British television screens titled Radio Times Guide to TV Comedy, published in 1998 and updated in 2003, also available online as the BBC Guide to Comedy until 2007. He has also written Funny, Peculiar, a biography of Benny Hill, published in 2002.[dead link]
In the past, Lewisohn has written for magazines, including the Radio Times and Match of the Day. He also helped to edit the book Hendrix: Setting The Record Straight, written by John McDermott and Eddie Kramer.