Dover began in 1941 in a Forest Hills apartment in Queens, where Hayward Cirker and his wife Blanche set up a small business. Cirker had briefly worked in publishing and wanted to be his own boss, so he started by selling remaindered textbooks. The company took its name from the apartment building. Its first book was Tables of Functions with Formulas, a German reference work for physicists, mathematicians and engineers. Cirker reprinted it after learning that the federal government had voided its copyright during the war, photographing the pages and printing them by offset so he could skip a typesetter. That habit of reissuing out-of-print and out-of-copyright works cheaply became the house method.
By 2000 Cirker had died, and Courier Corporation, a book manufacturer, bought all of Dover's stock for 39 million dollars in cash. Dover was then based in Mineola, New York, with more than 7,000 titles in print across over 30 specialty categories. Its customer-care address today is in Garden City, New York. Ownership has changed hands since then.
The list is wide. Dover reprints classic literature, classical sheet music, math, science and engineering texts, and collections of public-domain illustration. It also serves narrow audiences such as woodworkers, and it has issued graphic novel reprints since 2015. Children's and adult coloring books sit alongside the graduate-level math. Most titles are photo facsimiles of the original editions, with the original pagination kept and often a new cover.
Your Huckleberry Finn most likely comes from Dover Thrift Editions, the classics line that debuted in 1990. The Thrift edition of Adventures of Huckleberry Finn by Mark Twain, first listed in 1994, runs 224 pages. A separate Thrift Study Edition of the novel exists too. Expect a small, inexpensive paperback with the complete text and little else. It is a book for reading on a bus or marking up for class, not a collector's object. If you liked how it felt, the same line includes many other novels, plays and poetry collections, and the wider Dover catalog goes far beyond fiction.