I am trying to figure out which William Frazer (Fraser, Frazier) is my 4G grandfather. He would have been born possibly between 1750 and 1771, possibly in Scotland. I want to look at any records for a William Fraser coming over of that age.. or of his father or grandfather. In other words I want to track the different stories and try to document them. David Dobson has many books on the market with lists of various Scottish emigration. Are his books reliable sources of information?