Carver is often mistakenly credited with the invention of peanut butter. By the time Carver published "How to Grow the Peanut and 105 Ways of Preparing it For Human Consumption" in 1916, many methods of preparation of peanut butter had been developed or patented by various pharmacists, doctors and food scientists working in the US and Canada. The Aztecs were known to have made peanut butter from ground peanuts as early as the 15th century. Canadian pharmacist Marcellus Gilmore Edson was awarded (for its manufacture) in 1884, 12 years before Carver began his work at Tuskegee.