Zalman Usiskin is an educator best known as the Director of the University of Chicago School Mathematics Project.
A faculty member since 1969, he also has taught junior and senior high-school mathematics and has authored and co-authored many textbooks, including a six-volume series used as part of the University School Mathematics Project secondary curriculum.
In recognition of his work, he has received a Lifetime Achievement Award from the National Council of Teachers of Mathematics.
Usiskin's doctoral dissertation in mathematical education at the University of Michigan involved the field testing of his book, Geometry: A Transformation Approach, which was written with Arthur Coxford.
This book has greatly influenced the way geometry is taught in many American high schools, according to the NCTM citation.