James MacKay provides you with a brief history of the tartan, and then goes on to include several of these tartans, ranging from very early tartans of the highlands to newer commemorative tartans.
My personal problem was that my family is not a clan and falls under one or more clans, and I'm not sure which would be the appropriate tartan to wear. You can't hold the author responsible, but if you are doing some family history research you may encounter the same problem. So you may have to do some independent study to find out which clan you belong to.
But even with my personal problem aside, it is an excellent resource and has something to teach about Scottish history.