Louis Plack Hammett offers a modern reminder of the classical challenge in organic chemistry to adapt methods from physical chemistry. The main method that Hammett offered the field is the use of quantitative statistics in measuring the relationships of substances in organic chemical reactions. The equation n amed after him describes specific effects that can be expected in reactions of a wide range of substances. The acidity function that he calculated provided a model for describing unseen reactions of acids and bases. This was particularly appreciated in areas that would have been restricted by difficult laboratory conditions.

Hammett was born in 1894 and spent most of his childhood in Portland, Maine. After graduating from Harvard University, he traveled to Switzerland for graduate work. He returned home in less than a year when America entered the First World War. After the war, he attended Columbia University for studies leading to his Ph.D. While a graduate st udent, he taught chemistry classes and continued as professor after earning his doctorate in 1923. He wrote three notable textbooks on chemistry. In these books, he made the effort to convince the student that the methods of studying physical chemistry were equally appropriate for the study of organic chemistry. He died in 1987.