The article in which he presented the theory of binary evolution in stellar dynamics[1] (often referred to as Heggie's law) has found an outstanding spectrum of applications in many astrophysical domains.
One of the originators of the current paradigm of the dynamical evolution of collisional stellar systems, he has made seminal contributions also to the quantitative study of prehistoric mathematics and astronomy.
On these subjects, he has authored or co-authored of two books: The Gravitational Million-Body Problem: A Multidisciplinary Approach to Star Cluster Dynamics[2] and Megalithic Science: Ancient Mathematics and Astronomy in North-west Europe.
Following his appointment to a Lectureship (1975) at the then Department of Mathematics in Edinburgh, his entire professional career has been based there, with prolonged research visits to Princeton,[5] Cambridge, Kyoto, and Warsaw.
Among other indicators of esteem, he has served as the President of Commission 37 of the International Astronomical Union,[7] on the Council of the Royal Astronomical Society of London (Triennium 1982–1985), as an Editor of long standing of its main research journal, Monthly Notices, as well as an Advisory Editor of the Journal for the History of Astronomy.