Although there are some critics who admire Love's Pilgrimage and Sylvia, and though there is much in both books to show the diversity of Sinclair's talent, it seems to me that King Coal (1917) is the first book after The Jungle to indicate his full power as a novelist of the social scene. If the people of the upper class are sometimes stiff and inhuman, the workers have great vitality; and so has Hal, the aristocratic hero. What is most impressive in King Coal, however, is the evidence that Sinclair had learned how to assimilate the vast quantities of information his restless mind collects. There are no solid blocks of exposition in King Coal as there are in The Jungle; the documentation is there, but it is an essential part of the story.
Rather surprisingly, Sinclair did not continue the artistic advance made in King Coal. The fiction written between 1917 and 1927, when Oil appeared, is mostly trivial and inferior. But within that decade Sinclair did write his great series of pamphlets…. All of these books have the same virtues and the same faults. For example, both The Brass Check and The Goose Step, which had the greatest influence, are tremendous collections of facts—facts of the most startling import to anyone who had believed that our great newspapers and our great universities were as impartial as they pretended to be. To have these facts brought together was sensational and extremely useful. On the other hand, as many critics gleefully pointed out, trivial incidents, often out of Sinclair's experience, were treated in as much detail as scandals of national magnitude, and the very quantities of factual material tended to get in the way of an understanding of journalism or education as such. Yet, whatever their faults, these books stand as examples of muckraking at its best: the patient quest for information that men have done their best to conceal and the fearless publication of what these same men are determined, by whatever means necessary, to keep unknown. (pp. 214-15)
