She also wrote novels for teens and was twice a Newbery nominee in the 1970s. As you'll see, she wrote two other culinary books.
Apparently, she committed suicide, but I can't find a full obit. Here's what I did find:
Local author, professor Katie Letcher Lyle dies | The News-Gazette
www.thenews-gazette.com/content/local-author-professor-katie-letcher-lyle-dies?fb...
Aug 25, 2016 - Katherine "Katie" Letcher Lyle, 78, of Lexington, author of more than 20 books, died Wednesday, Aug. 24, 2016. Lyle's books reflected her wide ...
http://katieletcherlyle.com/index.php
(her site)
http://www.goodreads.com/author/show/47169.Katie_Letcher_Lyle
(reader reviews and covers)
WRITINGS BY THE AUTHOR:
(With Maude Rubin and May Miller) Lyrics of Three Women, Linden Press (New York City), 1964.
I Will Go Barefoot All Summer for You (young adult), Lippincott (Philadelphia, PA), 1973.
("Chronicles the experiences of a thirteen-year-old girl during the summer she falls in love for the first time.")
Fair Day, and Another Step Begun (young adult), Lippincott, 1974.
("Convinced of the rightness of her love, a pregnant sixteen-year-old follows the father of her child when he runs away from her.")
The Golden Shores of Heaven (young adult), Lippincott, 1976.
Dark but Full of Diamonds (young adult), Coward (New York City), 1981.
("In love with the woman his father also loves, a sixteen-year-old has trouble accepting their impending marriage.")
Finders Weepers (young adult), Coward, 1982.
("During a visit to the home of her dying grandmother in the Blue Ridge Mountains, Lee happens on a famous lost treasure which may prove unlucky for herself as well as for others.")
Scalded to Death by the Steam: Authentic Stories of Railroad Disasters and the Ballads That Were Written about Them, Algonquin Books (New York City), 1983.
The Man Who Wanted Seven Wives, Algonquin Books, 1986.
The Wild Berry Book: Romance, Recipes, and Remedies, North Word (Minocqua, WI), 1994.
(Editor with Roger Jeans) Letters from Peking: The Wartime Letters of U.S. Marine Captain John Seymour Letcher, 1937-1939, U.S. Marine Corps Historical Society, 1996, Ohio University Press (Athens, OH), 1998.
The Foraging Gourmet, Lyons & Burford (New York City), 1997.
When the Fighting Is All Over: The Memoir of a Marine Corps General's Daughter, Longstreet, 1997.
The Complete Guide to Edible Wild Plants, Mushrooms, Fruits, and Nuts: Finding, Identifying, and Cooking, 2004
More later...