In this paper I present an overview of the life and work of Donald MacCrimmon Mackay, a distinguished Christian polymath who made significant contributions across a number of domains in science and philosophy in the middle part of the 20th Century, and the centenary of whose birth was in 2022. After a brief biographical sketch, we will review his contribution to theology & science, the main ones of these being: complementarity, an innovative concept relating information and matter, and mind and brain; and logical indeterminism, a proposed solution to the problem of free will and determinism. I hope that this overview will stimulate interest in, and further exploration of, his ideas. [ABSTRACT FROM AUTHOR]