Barnett Rich (deceased) held a doctorate of philosophy from Columbia University and a doctorate of jurisprudence (J.D.) from New York University. He taught at CUNY and Columbia University and was Chairman of Mathematics at Brooklyn Technical High School for 14 years. Rich authored 23 books, including Schaum's Outlines of Elementary Algebra, Modern Algebra, and Review of Elementary Algebra.
Christopher Thomas, Ph.D. is Professor of Math at Massachusetts College of Liberal Arts. He received a doctorate of philosophy from Tufts University. He is the author of Calculus Success in 20 Minutes a Day and Trigonometry Success in 20 Minutes a Day.