George Simmons arrived at the college after teaching at Williams College, the University of Rhode Island, Yale University, the University of Maine, and the University of Chicago. He studied Banach algebras during his dissertation work and his mathematical interests remained firmly rooted in classical analysis. He found existing textbooks "dreadful" (especially at the high school level) and proceeded to right the situation with a succession of his own texts:

• Introduction to Topology and Modern Analysis (1963)
• Differential Equations with Application and Historical Notes (1972, 1991 (2nd ed.))
• Precalculus Mathematics in a Nutshell (1981)
• Calculus with Analytic Geometry (1985, 1996 (2nd ed.))
• Calculus Gems (1992)

Simmons has a remarkable facility for expressing the essence of mathematical ideas in clear direct language, and this writing style has earned him an international reputation. Through the title pages of his texts, the name of Colorado College became known to the mathematical and educational communities world-wide in a way reminiscent of the days of Florian Cajori.

Simmons maintains strong opinions about the downward path of modern education, and as one might expect, was never a fan of the block plan. Yet he was a clear and engaging teacher, while ensuring that his time for textbook writing was not too cluttered with other college tasks.