Read this book and find out for once and all what the big deal about a II V I progressions are. According to Schenker all art is deeply rooted in and imitative of "nature" - - though at times he admits that reconciliations with natural law are required. - - Is this true? Well a whole debate about nature vs. artifical society and the whole realm of aesthetic philosophy can arise outside this book, and one can get into a whole lot of hoo-ha that most musicians don't usually think of when we're tapping our feets to the changes. Schenker however thinks and observes a lot. Unlike most theoreticians he was anything but dry... he was actually a creative thinker writing a plea for musicians to be both *creative* and scientific... this book represents the beginings of his efforts to do so... and it is nothing less than engaging, if not provocative.
Over 100 years have past since this book was written. Much of the material on a practical level has been absorbed into mainstream music theory, though in much simpler terms. What makes this book so amazing (besides being "the source") is that Schenker reveals the philosophy underlying musical ideas which we take for granted as "common sense today" (*not to give the wrong impressions, some of his ideas, of course, are debated!) - - Ironically, while much of the practical end theory is definitely modern day common sense, some of the philosophy is - - interesting to say the least, at times a majorly enlightening and different way of looking at things, at other times head scratching "wuh?" or realizing that he definitely was a product of his era. Schenker is also fascinating due to his wry sense of humor as well and ability to draw examples from the most mundane aspects of daily life to the behaviour of the notes (to back his claim that true art imitates nature.)
All in all, I should warn you... today's music theory books have a tendency to "dummy down" - - Musical theoreticians may be "authoritive" but they are rarely original, and even when they are they don't like to be too profound... Schenker however is a German Philosopher with a capital "G" and "P", as a result, if you're a typical musician looking for something move along the lines of a typical "Theory Made Simple" book, move on.... this book definitely requires a lot of thinking and absorbing. In the end, if you can and are willing to deal with it, you will not walk away from the book - - if not a bit confused, definitely seeing LIFE as well as music very differently !
Now on to Schillinger...