"I was born in March 1955," writes David Hajdu in Love for Sale, "the same month Blackboard Jungle was released. I've always liked to think that I was born at the same time as rock and roll."

In his new book, Hajdu combines personal anecdotes with historical accounts of the evolution of popular music. Hajdu's writing about music is more engaging than his writing about himself, but the way he blends the two is in keeping with his thesis that pop music is "a phenemenon of vast scale and intimate effect, a product of mass culture that reaches millions of people (or more) at one time and works for each person in a personal way."

Hajdu is the author of books including Lush Life: A Biography of Billy Strayhorn (1996) and Positively 4th Street (2001). Perhaps the most fascinating book ever written about Bob Dylan, Positively 4th Street looks at Dylan in the 60s through the lens of his friendships with Joan Baez, her sister Mimi, and Mimi's eventual husband Richard Fariña. Hajdu has a knack for putting music in its social context without diminishing it to merely a product of mechanical factors, and that gift is evident throughout the highly readable Love for Sale.

An important clarification: by "pop music," Hajdu doesn't mean just Top 40 fodder. He means all of popular music, starting with sheet music: a primary means of songs' dissemination and sale in the early 20th century. As Hajdu notes right off the bat, many of the criticisms now leveled at pop songs have been heard for over 100 years: in 1910, the New York Times complained about the commoditization of songs, which were purportedly "manufactured, advertised, and distributed" like shoes from a factory.

That's not to say that nothing has changed under the sun: Hajdu argues that the rise of recording technology, and then portable playback technology, has emphasized the acutely personal nature of pop music consumption. Classical pianist Glenn Gould famously said that the ideal performer-to-audience ratio was "one to zero," as he forsook the live concert stage for a hermetic existence in the recording studio. That's increasingly the way we consume and understand music.

Love for Sale isn't a landmark work of original scholarship: it's a chatty and loose walk through the history of popular music through the 20th century and into the 21st. If you don't know much about pop music history, you'll glean plenty of new and accessible insights; if you do, on the other hand, you'll appreciate Hajdu's gift for pithy formulations that crystallize intriguing arguments about music. Among those arguments:

● The pop charts are best understood as a form of entertainment in and of themselves: a sort of performance by the entire music industry, which tallies "hits" based on a changing metric that captures actual sales imperfectly and captures influence even less perfectly.

● When country music replaced its "hillbilly" image with a "cowboy" image, it was a way for the genre to keep its rural associations while extricating itself from the roiling racial politics of the South.

● The fact that it was Elvis Presley who broke rock and roll into the commercial mainstream is ironic, given that he can be seen as the last relic of an era where singers and songwriters were separate. Chuck Berry, a self-contained music-making force, was the artist who more accurately "pointed to the near future of pop music," argues Hajdu.

● The album as it evolved in the 1960s — with Pet Sounds being "the ur-text of the LP as an art form" — was strongly influenced by another great American art form, the Broadway musical. Hajdu points out that even as the "concept album" was evolving in the rock world, cast albums were among the biggest-selling LPs.

● Hip-hop, distinguished as the first major musical form to use recorded music itself as an instrument, "anticipated the transformation from analog culture to digital culture and prepared the world for that change."

● One of the signal accomplishments of Michael Jackson was to establish "the ability to dance as a prerequisite for pop stardom for decades to come."

The book is worth reading if only for two virtuosic passages: one in which Hajdu tracks the way Bessie Smith's 1920s blues were reinvented as big-band swing (think Benny Goodman), then as jump music (think Big Joe Turner), then as country swing (think Hank Williams) before becoming "rock and roll" in the hands of Ike Turner, Bill Haley, Elvis Presley, and Chuck Berry. In another passage, Hajdu celebrates disco as a genre that restored dance to centrality in pop music — and, not incidentally, became the soundtrack for gay liberation.

Hajdu's integration of personal anecdotes with all of this helps to establish his bona fides (he blew out an ear by sleeping on a transistor radio, he called Springsteen in the studio while Born to Run was being recorded, he got his first Sony Walkman at the portable player's 1979 launch event, his wife knows all the lyrics to "Rapper's Delight"), but otherwise doesn't add much to the book. It's about the music, man.