The one that got away
My colleague wrote his book review laying out all of the evidence about it. How much was plagiarized you ask? I'll just quote Bob Frizzell:
About half of both the substance and the wording of the first 180 pages of this book duplicate Theodore Huebener's The Germans in America (1962). This process begins on page 36 of the work, where several lengthy sentences are repeated from page 3 of Huebener's book. By page 39 of Tolzmann, only 29 of about 400 words on the page do not appear on pages 5 and 6 of Huebener. The next page of Tolzmann (page 40) has, by my count, only nine words that are not on pages 6 and 7 of Huebener.
To be sure, Tolzmann acknowledges Huebener. In the preface, he says, "I leaned heavily on Huebener, especially for the period from the American Revolution through the Civil War" (p. 12). But this is an entirely inadequate and quite misleading description of what was done in the production of this book. Most of the text on pages 65-78 directly duplicates pages 25-41 of Huebener, and this material concerns the period before the Revolution. Wherever he uses a long passage from Heubener, Tolzmann omits an occasional word, phrase, sentence, or even a couple of paragraphs. For example, on page 97, by my count, only 5 of the approximately 400 words on the page do not repeat pages 44-46 of Huebener, but at one point two paragraphs of the original are omitted and at another point, a sentence of the original is dropped. Sometimes Tolzmann inserts a word, sentence, or even paragraph of his own. Occasionally he reverses the order of two of Huebner's phrases. Even in the first half of this book, there are sections as long as twenty pages that do not come from Huebener.
Huebener's words are not put in quotation marks or indented.
Well what do you think has happened since? Unlike other more prominent plagiarizers, this guy apparently has just continued on like nothing ever happened.
Heck, his book is still available on Amazon! He's still the director of a German-American studies program at a major research university!