Kenneth Ireland [1937-1991] was Professor of Mathematics at the University of New Brunswick, Canada. Before UNB, he held positions at Johns Hopkins, Brandeis, Brown, Bowdoin, and a visiting membership in the Institute for Advanced Study. Known for his broad interests and active involvement in all areas of departmental life, he had a lasting impact on generations of students as a teacher and mentor. His widely acclaimed book with Michael Rosen, A Classical Introduction to Modern Number Theory, appears in the series Graduate Texts in Mathematics. Al Cuoco is a Distinguished Scholar at Education Development Center in Massachusetts. Before EDC, he taught high school mathematics for 24 years to a wide range of students in the Woburn, Massachusetts public schools. At EDC, he works in curriculum development, professional development, and education policy, and for over three decades, he has worked with Glenn Stevens in the PROMYS for Teachers program atBoston University. His mathematical interests and research publications lie in algebraic number theory.