Even if you had no prior curiousity about Switzerland, this book would pique your interest. The author's stated aim is to create a multidisciplinary narrative, in the tradition of the Enlightenment (Johnson, Gibbon), explaining...well..."Why Switzerland?" - i.e. how did Switzerland arise, persist, and come to be so aggressively ecclectic?
And the author has some work to do. Not unlike the 'bacterial flagellum,' Switzerland's spectacularly improbable emergence from the fabric of history could be invoked by creationists to support a 'design inference.' It is, to paraphrase Michael Behe, as though a 747 spontaneously assembled itself and took flight.
Of course, Steinberg's answer to "Why Switzerland?" is much more interesting than "God did it." It cannot be summarized, but involves grain prices, the halberd, high-altitude athletic training, cottage industry, credit and interest and William Tell. At the very least, it has something to teach us about federalism, decentralization, peaceful coexistence and martial virtue.
For me the most fascinating part of this was to see how resistance to the Hapsburgs and then Napolean created a culture of decentralized disorganization - the opposite of Absolutist/Enlightenment France. The Swiss come across like the Duke Boys of central Europe ("Someday the mountain might get'em but the law never will..."). But this culture of rebellion also stands in contrast to Germany's stark tradition of blood and soil reactionism. Napolean's influence on Germany sowed the seeds of the World Wars. In Switzerland it acted as a sort of positive selection pressure, perturbing Alpine society and provoking its organization into Alpine civilization.
This is a very dense book, with more obscure names and places than a Russian novel. Some independent reference material (i.e. map, Wikipedia) is useful to figure out just which Johann is which, and to distiguish the various mountain passes from one and other (passes being the primary geographical feature and navigational reference point for most of the nation's history). But a reader's close attention to this book will be very well repaid.