Of all the subjects/icons to explore in the multi-faceted world of pop culture, it is safe to say that John Lennon and all things The Beatles have been systematically and obsessively catalogued--whether the film in question is a documentary or a more stylized rendering, as is the case with Sam Taylor-Wood's Nowhere Boy.
What separates this particular film from some of the rest of its ilk is the fact that it is based on a memoir by Julia Baird called Imagine This: Growing Up With My Brother John Lennon (a real subtle title, by the way). This memoir, incidentally, was not the first that Baird, who shared John's beloved mother Julia Lennon, has penned. The other was released in 1988 and called, in yet another bid for clinging to celebrity, John Lennon, My Brother (legitimized by a foreword from Paul McCartney). I suppose Baird didn't want to split hairs in this instance either by referring to Lennon as her half brother.
Another distinguishing factor regarding this film is just how heavily it focuses on Lennon's highly intense relationships with both his mother and his Aunt Mimi (who raised him as her own child from the time he was five years old). Along with Lennon's Uncle George (played by David Threlfall), Mimi ensured John's well-being in the face of Julia Lennon's erratic behavior and lack of self-control when it came to men. But, at around the age of 16, when Lennon's Uncle George died, Julia reintroduced herself into his life, an occurrence that was initially a source of elation for Lennon, but soon turned into yet another glaring familial disappointment. Once Lennon had grown deeply attached to Julia (especially after she had shared her deep love of American music with him), she, true to form, caved into the demands of the man in her life (her second husband Bobby Dykins), who insisted that Julia already had two other daughters to raise that needed her more than Lennon.
This sudden desire to distance her son from her life comes at a bit of an inopportune time for Lennon, recently suspended from school for carrying around "pornography" with him (a.k.a. a titty rag). Rather than tell Mimi about this indiscretion, he has instead been relying on Julia for a place to go during the day whilst he is supposed to be in school. Now that Mimi has been made aware of how willing John is to cast her off in favor of her sister, she seems to soften a bit more, even encouraging him in his quest to start a rock n' roll band.
While there are various events in Nowhere Boy that appear more than a little questionable, such as John saying, "Why couldn't God have made me Elvis?" and his mother responding sweetly, "Because he was saving you for John Lennon" or the manner in which John is first introduced to both Paul McCartney and George Harrison, screenwriter Matt Greenhalgh (the brilliant mind responsible for the Ian Curtis/Joy Division biopic Control) uses the source material to the utmost advantage, extrapolating from the memoir as much high drama as possible.
The primary fault with Nowhere Boy, however, is that, as a viewer, there really isn't any new information to be gleaned from the film (accentuated tenfold when taking into account the sort of Beatles enthusiast that would go into it with a considerable amount of foreknowledge). Yes, John Lennon was deeply affected and emotionally damaged by how callous and often flighty his mother was. It more than likely shaped the rebellious rock star persona he so carefully cultivated. But we already knew that. What Nowhere Boy subconsciously reiterates, though, is how inconsequential Ringo Starr and Cynthia Powell are with respect to their total absence from the story.