John Erskine of Carnock

However, the post of Professor of Scots Law at the University of Edinburgh became vacant in 1737, with the death of its incumbent Alexander Bain.

The University is a modern (that is, a post-Reformation) foundation, so the appointment of professors lay with the Town Council, which asked the Faculty of Advocates to suggest two names.

Seemingly, his lectures were very popular and he decided to produce an up-to-date text for his students to replace James Dalrymple, 1st Viscount of Stair's much used Institutions of the Law of Scotland.

Erskine's own work, Principles of the Law of Scotland, bore the imprint of Mackenzie's book in its organisation.

It had, and has, its critics - there are places where its posthumous publication is all too apparent, and many felt it was far too academical (with a poor feel for the daily practice of law) but it quickly gained a reputation as a reliable reference point and, probably, no book has been cited as frequently in Scottish courts.