During my usual week away from the computer, circumstances too uninteresting to relate caused me to read three nonfiction books at the same time, very different in subject matter, degree of scholarliness, and time period.
The Untouchables (1957) by Eliot Ness with Oscar Fraley. The true story of the battle against Al Capone and other gangsters during the Prohibition era. Presumably written by Fraley from information supplied by Ness. Written more like a novel than an autobiography. Probably mostly accurate, unlike the highly fictionalized TV series or the extremely fictionalized movie.
The Pueblo Revolt (1970) by Robert Silverberg. The well-known SF writer provides an account of the successful rebellion of Native American peoples under Spanish rule in the American Southwest during the late 17th century. Written for the lay reader, without footnotes and such, but based on scholarly sources. My edition is a 1994 reprint from the University of Nebraska, which seems to indicate that it's a respectable work of history.
Same Time, Same Station: Creating American Television, 1948-1961 (2007) by James L. Baughman. Covers the subject matter in the subtitle, as networks, sponsors, and others tried to figure out what to do with this new medium. Would it be like live theater, radio, or the movies? A very scholarly, but readable work. The footnotes and such take up roughly 150 pages in an approximately 450 page book.