Hilburn was a music critic for several decades, writing mostly for the Los Angeles Times. Despite the title, this book isn't solely or even mostly about Lennon. It is a career retrospective memoir (not a collection of articles) about the stars who meant the most to Hilburn. As one might expect from a music writer, this "memoir" is more about his interactions with stars than it is about his personal life (the latter is barely mentioned beyond the first quarter of the book).
He devotes special attention to a handful of performers he feels have advanced music to a new level, including Elvis Presley, Johnny Cash, Bob Dylan, Bruce Springsteen, and Bono. If the book and Hilburn's career have an overall theme, it is the quest to identify "the next Elvis." There is little about those he considers inconsequential, a list that includes many bestselling but lightweight artists. Punk and metal fans may be disappointed with minimal coverage (I was surprised there was nothing about X or Guns N' Roses (except one quote from Axl Rose) -- Hilburn largely ignores the local L.A. scenes), while rap/hip hop fans will be amazed that a white guy in his fifties "got" their music in the 1990s.
Almost any rock or country fan with broad interests should enjoy Corn Flakes with John Lennon. Others should check the index for their favorites before purchasing.