Dr. Ron Larson is Professor of Mathematics at Penn State University at Erie. He received his doctorate in mathematics from the University of Colorado in 1970. Starting with Calculus in 1978, Larson has authored or coauthored over 200 mathematics textbooks and media products, including, in 1998, the first mainstream calculus textbook to go online. In 1983, Larson started his own publishing enterprise devoted to producing student-friendly math textbooks from sixth grade through college level calculus. Larson Texts, Inc., now includes a separate division for online mathematics learning materials, TDLC.COM, as well as Big Ideas Learning, LLC, which focuses on middle school math.