Tune In, which is the first volume in Mark Lewishohn's three part biography of the Beatles is a fantastic book. It's a brick of a book, running to 800 pages, that looks at the band and goes right back to the origins and childhood of each member, and tracing their early years in Hamburg. Lewisohn also draws on previously unavailable material, some great interviews and transcripts recorded by the band's first manager Brian Epstein. It's a terrific read