Nicholas Lemann, Farrar, Straus & Giroux, 320 pages, $28. In academia and in the headquarters of capitalism, attitudes toward business have oscillated wildly, Nicholas Lemann writes in "Transaction Man." His ambitious book is an unusual addition to a growing canon that seeks to explain why, for many ordinary people, the American dream has come to seem out of reach. Rather than focusing on macroeconomic factors such as growth, productivity or unemployment, Lemann dwells on how companies are run. Its publication is timely, given the recent statement by the Business Roundtable, a group of bosses, that firms should be run for all stakeholders, not just shareholders. Lemann gives a primer on American business history, breaking it down into phases, the most current of which is the era of Network Man, led by tech firms seeking to overthrow the old order with platforms that have millions of connected users. The jury is still out on whether this latest phase is an improvement, the book suggests. As an intricate feat of storytelling, the author, a writer for the New Yorker, just about carries it off. There is rich reporting — and dazzling passages. Yet for all the sparkle, the book has a smoldering identity crisis: It can't make up its mind whether it is a polemic about how America has gone to hell or a more standard history, anchored in empiricism. It also does not offer a solid framework for how a well-functioning economy works. As a result, the reader often has the uneasy feeling of not being given the full picture.