Alexander Graham Bell, the inventor of the telephone, left behind many inspirational and prescient quotes. He emphasized the importance of speech and life, encouraged leaving beaten paths to discover new things, and stressed that preparation is key to success. Bell also noted that when one door closes another opens, and that every experiment contains a lesson. Some of his quotes from 1906 onward proved remarkably forward-thinking, such as predicting video calling and that controlling air power would lead to global dominance. Bell also warned of limited fossil fuels and the potential greenhouse effect from their unchecked burning.