Grenville Kleiser was instructor in Public Speaking at Yale Divinity School, Yale University. His publications include "How to Speak in Public," "Great Speeches and How to Make Them," "Complete Guide to Public Speaking," "How to Build Mental Power," and "Talks on Talking." Successful Methods of Public Speaking states that the most important thing is sincerity. Unless you believe in what you are saying you cannot be successful. Kleiser says, "Therein lies the key to successful oratory. When the truth of your message is deeply engraved on your own mind; when your own heart has been touched as by a living flame; when your own character and personality testify to the innate sincerity and nobility of your life, then your speech will be truly eloquent, and men will respond to your fervent appeal."