He's got a point, and he lays it out in brief, easily consumed chapters that cover everything from the space program to jazz to modern art. There was a lot going in that year--in January, the Russians launched a capsule that was the first object to leave Earth's orbit. Fidel Castro was victorious in the revolution to topple Batista in Cuba. The microchip was invented. The FDA granted approval for the birth control pill, the most important element in the evolution of feminism. Berry Gordy founded his first record company. Miles Davis released Kind of Blue, and John Cassavetes made the first American independent film of note--Shadows. Naked Lunch, by William S. Burroughs, was published, and the courts decreed that D. H. Laurence's Lady's Chatterly's Lover, long censored, could be released.
That all may be true, but Kaplan is constantly moving the goalposts to cover that not everything he writes about fit in the calendar year of 1959. For example, he devotes a chapter to Allen Ginsberg's poem Howl, but it was not written in 1959. Instead he keys on a reading Ginsberg gave of the poem in that year. He writes a great deal about Jackson Pollack, who stubbornly died in 1956. And John Kennedy, who is a frequent topic, declared his candidacy for president on January 1, 1960. Oh, but for 24 hours!
I think that any clever writer could take any year in American history and make a case for it being pivotal. 1959 does seem like a good time to have been a hipster. The Beats were active, jazz was cool, Lenny Bruce and Mort Sahl were in the nightclubs, and R&B was just starting to get popular. As great as all that sounds, much of this culture was in the fringes, though. Kaplan doesn't spend much time on what was popular in that year, whether on TV, in the movies, or on the pop charts. The truth is that America was a homogenized slab of white bread, and the artists Kaplan writes about are akin to the small mammals that were darting around while the dinosaurs roamed the Earth. They would have their day, but not for a long time.
As engaging as this subject is, the book is not very well written. It reads like a college paper based on research from Wikipedia. Kaplan uses some lazy adjectives, such as describing an appearance by Bruce on The Steve Allen show as "lame," or Lucien Carr's arrest for murder "horrible." Also, the Mercury 7 astronaut was Deke Slayton, not Duke, an error made more egregious by Kaplan's revelation in the acknowledgements that he was fascinated with the space program as a kid, and had memorized all the astronauts names.
Kaplan writes about music for Slate, and its in his chapters on jazz that he is most effective. There is a chapter about Miles Davis and another about Ornette Coleman, and how they revolutionized the use (or non-use) of chords. It's all Greek to me, but Kaplan explains it well for the non-musical.
But I think Kaplan makes a mistake in his opening chapter by equating 1959 to this year, and the ascension of Barack Obama. The late fifties were a time when the seeds that would flower in the sixties were sewn, and I would love to see something like that happen again, but you can't really compare the eras like that. The way culture and media are distributed is so different. We may well be on the verge of another cultural revolution, but wishing alone, or the convenience of a half-century anniversary, won't make it true.