The Institutions of the Law of Scotland which were written by Viscount Stair over a period as yet undetermined but were first published by him in 1681, have a place in the history of Scots law which can be compared with that of Grotius's Inleidinge tot de Hollandsche Rechts-geleerdheid in the history of Dutch (and Roman-Dutch) law. Whether Stair knew or used this earlier work has never been conclusively established, but one result of the present study is to confirm the suggestion of Professor Feenstra that he may have used it at second hand through Vinnius's commentary on the Institutes of Justinian. What is not in doubt is that Stair used Grotius's De jure belli ac pacis and another result of the study is to show that he used that more than he openly acknowledges. It also emerges that Stair used Gudelinus's De jure novissimo more fully than appears from the express citations and that he seems to take other citations of authorities at second hand. In this matter and in other respects the study raises questions rather than answers them but it may point the way to further discoveries by application of the same method.