[2] Craig attended Agnes Keith, Countess of Moray in her final illness in Edinburgh in 1588, with the surgeon Gilbert Primose and the apothecary Thomas Diksoun.
[6] Craig wrote a manuscript "Capnuraniae seu Comet, in Aethera Sublimatio" addressed to his friend Tycho Brahe.
Tycho, although a Dane, was as much a part of German astronomy as the Scots Duncan Liddel and John Craig, or the Czech Tadeáš Hájek (Hagecius).
Craig may have been the person who gave John Napier of Merchiston the hint which led to his discovery of logarithms.
Anthony à Wood wrote that one Dr. Craig ... coming out of Denmark into his own country called upon John Neper, baron of Murcheston, near Edinburgh, and told him, among other discourses, of a new invention in Denmark (by Logomontanus, as 'tis said) to save the tedious multiplication and division in astronomical calculations.
[11] Napier himself informed Tycho Brahe, via Craig, of his discovery, some twenty years before it was made public.