On page 6 of the first chapter, the author mentions that, "Much of our knowledge of child and adolescent development comes from the work of psychologists and educators such as Jean Piaget, Beatrice and Arnold Gesell, Maria Montessori, Erik Erikson, and Lev Vygotsky. Over many years these experts observed, researched, and documented how children change from age to age and discovered common patterns of growth" (Wood, 2017, p.6).
All of these psychologists and teachers are highly respected in the field. I remember studying all of them in my undergraduate years.