Americans barbecued as a cooking technique). Researchers state that many tribes in Africa utilized a vegetarian/plant based diet because of its simplicity. This included the way food was prepared as well as served. It was not uncommon to see food served out of an empty gourd. Many techniques to change the overall flavor of staple food items such as nuts, seeds, and rice contributed to added dimensions of evolving flavors. These techniques included roasting, frying with palm oil, baking in ashes, and steaming in leaves such as banana leaf. Cookbooks Because it was illegal in many states for slaves to learn to read or write, soul food recipes and cooking techniques tended to be passed along orally, until after emancipation. The first soul food cookbook is attributed to Abby Fisher, entitled What Mrs. Fisher Knows About Old Southern Cooking and published in 1881. Good Things to Eat was published in 1911; the author, Rufus Estes, was a former slave who worked for the Pullman railway car service. Many other cookbooks were written by black Americans during that time, but as they were not widely distributed, most are now lost. Since the mid-20th century, many cookbooks highlighting soul food and African-American foodways have been compiled and published. One notable soul food chef is celebrated traditional Southern chef and author Edna Lewis, who released a series of books between 1972 and 2003, including A Taste of Country Cooking in which she weaves stories of her childhood in Freetown, Virginia into her recipes for "real Southern food". Another early and influential soul food cookbook is Vertamae Grosvenor's Vibration Cooking, or the Travel Notes of a Geechee Girl, originally published in 1970, focused on South Carolina Lowcountry/Geechee/Gullah cooking. Its focus on spontaneity in the kitchen—cooking by "vibration" rather than precisely measuring ingredients, as well as "making do" with ingredients on hand—captured the essence of traditional African-American cooking techniques. The simple, healthful, basic ingredients of lowcountry cuisine, like shrimp, oysters, crab, fresh produce, rice and sweet potatoes, made it a bestseller. Usher boards and Women's Day committees of various religious congregations large and small, and even public service and social welfare organizations such as the National Council of Negro Women (NCNW) have produced cookbooks to fund their operations and charitable enterprises. The NCNW produced its first cookbook, The Historical Cookbook of the American Negro, in 1958, and revived the practice in 1993, producing a popular