I completed my 36th year of university teaching and retired in 2015. My research work was in differential and complex algebraic geometry. I taught classes in San Diego for AoPS (Art of Problem Solving) during 2017-18 (precalculus) and 2018-19 (calculus).

For better or for worse, I've authored textbooks on abstract algebra, linear algebra, an integrated course in multivariable calculus/analysis and linear algebra, and (freely downloadable here) differential geometry.

With thanks to Patty Wagner, Cameron Zahedi, Cameron Bjorklund, Justin Payan, and especially to Eric Lybrand, my lectures—flaws and all—for my Multivariable Mathematics course at UGA can now be viewed on YouTube. This course is based on my text, Multivariable Mathematics: Linear Algebra, Multivariable Calculus, and Manifolds. I very much regret the barbaric prices levied by mathematics textbook publishers.

You can email me at shifrin (at) uga.edu with relevant questions.