Warren Purkel, Ph.D. is a clinical psychologist who studied at Princeton University and the Derner Institute of New York. He has spent thirty years doing psychotherapy and play therapy with adults ...view moreWarren Purkel, Ph.D. is a clinical psychologist who studied at Princeton University and the Derner Institute of New York. He has spent thirty years doing psychotherapy and play therapy with adults and children. Warren plays the trombone, sings a lot, and loves telling knock-knock jokes. His co-author “elle” is an imaginary person, but you’d better not say that to her face!view less