This book is the right arm for folks attempting to do genealogical research in Ulster. It only covers the top names and it generally uses the "definitive" resources for these names, though in some cases he does include local information. Those wishing additional information on Scottish, Irish, or English names needs to use his bibliography to start researching those in greater detail. The most important aspect of this book is that he shows that often a surname in Ulster can be of Scottish, Irish, or English background. Ie genealogical research is required to determine family origin. You won't learn it by looking it up in a book. However if you think the family is Scottish and find it in a Scottish surname book, you may be misled entirely because the name is also Irish. Or English.
For less common names, buy the CD with Griffiths Index and look it up yerself. This is very easy. You can also other all Irish CDs, for those who object to going to a library. Often the experts who write these books used indexes like Griffiths in composing their books. These resources are now available to us. IGI can be a bit misleading for surnames in Ireland because it doesn't have enough Irish sources to provide an objective look. Griffiths and the Tithe Applotment indexes are generally used.
Linda Merle (Admin - Scotch Irish list on rootsweb)