Not every collision, not every punctilious trajectory by which billiard-ball complexes arrive at their calculable meeting places lead to reaction. ... Men (and women) are not as different from molecules as they think.

I am a teacher, and I am proud of it. At Cornell University I have taught primarily undergraduates, and indeed almost every year since 1966 have taught first-year general chemistry.

I learned English, my sixth language at this point, quite quickly.

I came to a happy Jewish family in dark days in Europe.

Knowing without seeing is at the heart of chemistry.

Alan Rocke's Image and Reality does so many things vividly and convincingly: it shows how visual images led chemistry step by step to the reality of the microscopic world; how simple portrayals of the logic of substitution and combination were reified; brings to our attention the imaginative, neglected work of Williamson and Kopp; and takes a critical look at Kekule's daydream. And it beautifully delineates the essential place the imagination has in science. A rewarding, lively picture of chemistry in formation.

One day I discovered that one could get the barrier to internal rotation in ethane approximately right using this method. This was the beginning of my work on organic molecules.