This inexpensive little paperback is essential in learning about prewar lionels. Although I haven't looked much at the Train Sets and Accessories sections, the O gauge section lists most of the models and variations I deal with. There are excellent photos for selected items, three or four on right page opposite twenty or so items on left page. There certainly are more complete books on these Lionel trains, but these Doyle guides are great. (The prewar guide is also very good, and also has Standard Gauge and Accessory sections as well as the O gauge.)