David L. Cook is an American author and speaker known for his work in the fields of psychology and personal development. He has written several books that focus on improving mental health and well-being, often incorporating principles from cognitive-behavioral therapy. In addition to his writing, Cook is a sought-after speaker at conferences and workshops, where he shares insights on topics such as motivation, resilience, and emotional intelligence. His practical approach aims to help individuals and organizations achieve their goals and enhance their overall quality of life.