Sandra Alters holds a PhD degree in Science Education and a Master's degree in biology. Formerly of the University of Missouri-St. Louis and Salem State College (Massachusetts), Dr. Alters has authored several textbooks in addition to Essential Concepts for Healthy Living, a laboratory manual, a children's science book, many articles in professional literature, and over sixty chapters and features in books. Additionally, she has written the instructional design for a variety of science-related software products for students. With twenty-five years of teaching experience, Dr. Alters brings her educational expertise, background in biology and human biology, and extensive writing experience to the author team.