Cover The Light in the Forest — By http://pictures.abebooks.com/YRDSLBKS/299057778.jpg, Derived from a digital capture (photo/scan) of the book cover. Copyright held by the publisher or the artist. Claimed as fair use regardless.,
Photo Credit: Fair use, https://en.wikipedia.org/w/index.php?curid=10247768

Conrad Michael Richter —
Photo Credit: By Source, Fair use, https://en.wikipedia.org/w/index.php?curid=36707240

The Grapes of Wrath by John Steinbeck — First-edition (1939) dust jacket cover of
Photo Credit: By Jacket design by Elmer Hader. - Public Domain, https://commons.wikimedia.org/w/index.php?curid=91863504

Cannery Row by John Steinbeck — First-edition (1945) dust jacket cover
Photo Credit: By Illustrated by Arthur Hawkins, Jr. Published by Viking Press. Public Domain, https://commons.wikimedia.org/w/index.php?curid=91868980

Tortilla Flat by John Steinbeck — First-edition (1935) dust jacket cover
Photo Credit: By Illustrated by Ruth Gannett. Published by Covici-Friede. - Public Domain, https://commons.wikimedia.org/w/index.php?curid=91866032

Edward F. Ricketts, October 1937 —
Photo Credit: By Source, Fair use, https://en.wikipedia.org/w/index.php?curid=4963764

Of Mice and Men — First-edition (1937) dust jacket cover by the American author John Steinbeck
Photo Credit: By Illustrated by Ross MacDonald. Published by Covici-Friede. - Scan via Heritage Auctions Lot #36344. Cropped from the original image and lightly retouched., Public Domain, https://commons.wikimedia.org/w/index.php?curid=91868578

Guthrum — Cropped form A Victorian representation of Guthrum's baptism in 878
Photo Credit: Doyle, James William Edmund (1864) "Alfred" in A Chronicle of England: B.C. 55 – A.D. 1485, London: Longman, Green, Longman, Roberts & Green, pp. p. 52 Retrieved on 12 November 2010., Public Domain, https://commons.wikimedia.org/w/index.php?curid=12039383

Lothair II of Arles, king of Italy (House of Bosonids) —
Photo Credit: By commons.wikimedia.org - Four kings of Italy.jpg, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=81960192

Gisela of Friuli —
Photo Credit: By Odejea - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=74842486

Berengar swears fealty to Otto — Otto I, Holy Roman Emperor's victory over Berengar, winning Italy, drawing in the Chronicle of Otto von Freising (Manuscriptum Mediolanense), Schäftlarn, before 1177
Photo Credit: Public Domain, https://commons.wikimedia.org/w/index.php?curid=65754