This website is the still-growing, online "textbook" for the Musicianship I–IV course sequence at Charleston Southern University. Textbook is in scare quotes because this is neither a book, nor entirely comprised of text. But it is the main source of information, and the main resource for student reference, in those courses. (Students are also expected to purchase and make use of Gary Karpinski's Manual and Anthology for ear-training and sight singing—two excellent resources that are last on my list to be replaced by my own online materials.)
This website is meant to accompany "inverted" or "flipped" courses that largely follow an inquiry based model (see the Introduction to the inverted musicianship course). That means that my students only occasionally engage these resources as the first step in learning a new concept or skill. Rather, these resources are usually meant to follow an earlier stage of analysis or inquiry, or a study of models to be emulated. As a result, most of the pages on this site do not read like a textbook. They are somewhere in between prosy lecture notes and reference material, with minimal graphical or audio examples. This is on purpose. I sometimes ask students to find examples of things discussed in the text in the models they studied or performed in class, for example. I also try to design the resources to be easily referenced while performing a task—such as model composition. This necessitates short, pithy prose rather than elaborate, masterful exposition.
If you are looking for a book to read that will teach you music theory or musicianship skills independently, this probably will not work. It is designed with a particular kind of class in mind, which is collaborative and for which this is only a supplemental resource to the primary pedagogical tool—active engagement with the materials in the presence of peers and a professor.
If you are a theorist exploring different pedagogical models or schools of thought, you may find this site interesting. Standard textbooks are written with the typical lecture–homework–test/project model in mind, so this will provide a different pedagogical approach from those texts (many of which are excellent at what they do, of course). Also, standard textbooks tend to offer more standard (and, therefore, older) approaches to concepts, and in recent years the diversity of schools of thought represented by the most common textbooks has diminished (in my estimation). I, however, try to incorporate the best new theories and approaches into my materials, especially since some new developments are readily accessible and audible to undergraduate music students. I also am comfortable joining in with certain schools of thought, where there are competing views on the same issues. Thus, this site include concepts drawn from Gjerdingen's Galant schemata, Caplin's formal functions, Hepokoski & Darcy's approach to Sonata Theory, Jay Summach's refinement of concepts of pop/rock form (modeled after Hepokoski/Darcy's and Caplin's approach), and Quinn's harmonic function theory. If you are interested in pedagogical materials that draw on some of these newer theories, or a pedagogical approach that is unashamedly in line with the "Meyer School" and what Quinn calls the "neo-McHoseian" approach to harmony (though everyone else just calls it "Quinnian"), this site may interest you, as well.
This "textbook" is an open-source textbook. That means that you are free to use, modify, distribute, even sell its contents provided that you 1) attribute the original to me, and 2) pass on the same rights to others (which includes me!) by licensing your derivative work the same way I license this one. (See the Creative Commons license deed linked on the left/bottom of this page.) In fact, I highly encourage others to "hack" this book: supplement it, reword it, add examples, drop chapters, mash it up with another one. Not only will that mean a greater diversity of material available, but if you improve your version of this work with your hacks, I can use those improvements to make this resource better, too.
If you want to "fork" this textbook, either to deploy it for your own course without worrying about me changing it on you (this website is still very much a work-in-progress, after all), or to use it as the basis for your own derived work, click "View on Github" (above or to the left), log in (or sign up), and "fork" the project. From there, you can edit, add, or remove the text, graphics, and videos (all text is in the very user-friendly Markdown format), or the theme (HTML and CSS). You can also send me a "pull request," if you've made a change you think would be beneficial to add to this version. You can even download an individual file to convert into a Word document and distribute as a handout in class.
Happy reading, watching, and hacking!
Please email me with questions at kris DOT shaffer AT gmail DOT com, or follow me on Twitter or my blog. And if you make use of any of these resources, please drop me a line. I'd love to hear what you're doing with it.