This history of the 1920s was unpleasant reading, and quickly became a chore: partly because I'm already familiar with much of what happened in the 1920s, and consider it banal; partly because author Frederick Allan's attitude toward 1920s Americans and their culture is arrogant and snide throughout. He very obviously casts his lot with the 1920s intellectuals, whom he says openly and ardently hated American society; and when the history introduced H.L. Mencken and described his total contempt for middle-class Americana, more than once mentioning that Mencken likened his work to watching animals in a zoo, I perceived that Allan clearly sympathized. I don't, because I can acknowledge people's stupidity and superficiality without despising them for it.
Speaking of superficiality: despite being a classic, Only Yesterday well demonstrates the limitations of books of popular history, in that it's actually quite superficial in most ways. It largely ignores Calvin Coolidge and completely misses how unusual he was among American presidents; and, more to its detriment, it displays a total lack of interest in religion's influence in 1920s America, except when forced to (as by discussion of the Scopes trial).
Factual information presented in the book seems to be quite accurate--I can say that much. I want to own a copy for its informational value, but I'm glad to be finished reading it.