<<snipped>> I have an ancestor who was a 'Contractor' and built roads and a harbour in Scotland. I am still not sure exactly what his job consisted of. His son was an engineer so I think the Father was, too. <<snipped>> I would interpret that as the father being responsible for the employment of men and machinery (and horses!) to construct the things (or parts of things) according to a specification / plan previously agreed with someone. He is paid a sum of money from which he has to pay for the construction - wages, raw materials, etc. He therefore bears a considerable financial risk. He then has to hand over the road / harbour, etc. in working condition (assuming that's the contract) I would not think the father was an engineer himself - the government(?) engineer would have planned the route of the road (say), and the contractor would employ engineers to supervise the work. And the contractor in his turn would be supervised by the government(?) engineer. Certainly on railways, the engineers and contractors were very much separate people - the names of Stephenson, Brunel, etc (the engineers) survive, whereas the names of the contractors (with a few exceptions perhaps such as Brassey from Cheshire) tend to be known only to specialists. Now, having said all that, my understanding is fairly general on this and all sorts of exceptions might occur, especially on smaller projects where people might double up on roles. Adrian B