Dale Harbison Carnegie was an American writer and lecturer and the developer of famous courses in self-improvement, salesmanship, corporate training, public speaking, and interpersonal skills.
Source: wikipedia
Michael A. Crom is a business writer focused on leadership and professional development. He is the author of The Leader in You, a book that offers practical advice for those looking to improve their management skills.
Stuart R. Levine is a business consultant and author who focuses on leadership development. He wrote The Leader in You, a book that offers practical advice for professionals seeking to improve their management skills.