This was, in its time, a great guide to major European cities. It was accurate and easy to use. Each year, they added more and more cities. Now it is 44 cities and too big to carry in your pocket and contains second and third tier cities that are debatably "Main." I mean, who needs a guide to Toulouse?
Unfortunately, there is little choice: either you buy the whole thing or buy individual city guides which become very burdensome. Some of the detailed maps, which were always useful in pre-GPS days, are now gone. Still, a worthwhile reference for travelers.