The online Beethoven course given by pianist and Curtis Institute professor Jonathan Biss last fall was remarkable for all the things it wasn't. In an age of impatience and distraction, it was a slow, deep immersion. Biss currently is recording all 32 Beethoven piano sonatas, and, despite the course's golden opportunity for marketing synergy, he barely mentioned his own recordings, or his 18,000-word Kindle Single on the subject.

And in a medium that measures value through the distorting lens of hits and traffic, Biss managed to attract quite a bit of attention for the project, with lengthy coverage in the New Yorker and Gramophone. The purity of his mission cut a classical voice through the media noise. He made you believe that unless you know Beethoven's music and really understand the achievement, you are living in a diminished state.

Classical music accounts for less than five percent of recording industry sales. Who knew what kind of reception an online Beethoven course would get?

It got enough for Curtis to repeat it. An encore presentation begins Thursday - again for free. You can register at

Fans did not exactly beat down the doors the first time. Biss' Curtis/Coursera Massive Open Online Course (MOOC) drew registration of 35,150 from 124 countries. Impressive. But of those, only 21,149 signed on at least once. Many more dropped out.

The best statistic Curtis has to show for who was left standing by the end of the five-week course is the number of complete views of each video: about 800 for each of the 24 segments, which total 41/2 hours. Still, 1,841 students completed enough coursework to qualify for "a statement of accomplishment."

If these are attendance figures to get you thrown out of school, it's important to realize that they are typical of the low commitment level of life online. A December University of Pennsylvania analysis of a million enrollees in 16 Penn/Coursera courses found that completion averaged just four percent. By that standard, Beethoven did all right.

For Curtis, which is developing relationships beyond its bonds with the 160 or so prodigies it educates each year, the Coursera foray cracked an important door. Students in a post-course survey were asked what impact the course would have on their future musical experiences. Under the pursuit of listening to music, 62 percent reported "strongly favorable" expectations; in its impact on attending future performances in person, 44 percent said they felt "strongly favorable."

Biss doesn't play a note until more than a half hour into a talk that covers Bach, Haydn, and Mozart; the important evolution of composer from servant to free-lancer of self-determination; and the sonata form as the enduring contribution of the classical era. Even then, all we get is a B-flat major scale.

Biss does eventually play parts of the sonatas. But mostly he sits at the piano. And talks.

Before he gets to Beethoven, he says quite a bit that vaults elegantly across the professional musician-music appreciation ravine. Insight is concentrated, so much so that extremely powerful ideas can slip by unheralded.

"The work that historians and musicologists do is not, or least should not be, purely theoretical," he says. "On the flip side, performance should not be purely intuitive."

Should not be purely intuitive. Here again, the statement is remarkable for what it is not. Classical music has labored to establish a firm principle in the mind of the consumer: that performance is spontaneous passion. Music is about feeling, of course, and without the emotion, music is nothing. But the point Biss is making is that there is a structure to be heeded. "We performers need to be acutely aware of the backdrop of the music we play, of the world that produced it and the way in which it is put together."

The psychological effect of music comes from the structure, and from the unfolding of harmony.

"A teacher once told me that to study musical structure is to create a map of the emotional content of a piece of music," he says. "No one has ever told me anything truer or more useful."

Biss here is standing on the shoulders of musical insiders such as Charles Rosen and Joseph Kerman, but, just as significantly, on once-popular writers such as James Huneker and B.H. Haggin. As Haggin used the primary media of his day - the book, dotted with musical notation that he knew his musically literate readership would understand - so too does Biss accurately judge the media and audience of his time. He is essentially doing now what Haggin did, in 1944, in Music for the Man Who Enjoys "Hamlet."

But Biss focuses on a small repertoire. Why, of all of Beethoven's works, are the 32 piano sonatas worthy of close inspection? As the laboratory for Beethoven's most experimental ideas "and for Beethoven's most private thoughts," Biss says, they were the most innovative works of a singularly innovative mind.

He makes the point that the sonatas and quartets were home music, not concert music, and this meant liberation. "Beethoven did not really need to think about the limitations of players or the lack of rehearsal time, inadequate conditions, etc. . . . The removal of this impediment meant that Beethoven's imagination could be fully engaged in a way that it probably couldn't with the symphonic music."

By the time Beethoven finished writing the 32 sonatas, Biss says, "he left music a permanently altered art form."

You don't need training in Schenkerian analysis to understand the course (though discussion of key relationships will likely lose some). Inevitably, the most effective parts of his discourse are about emotion - how Beethoven, in breaking with convention of the classical era, demolished the accepted boundaries of drama. To Biss, one well-known sonata becomes "a serious haze of sound"; it moves the listener to an "altered state," and grows into a "terrifying id." All these claims are supported by solid musical analysis.

Most thrilling is the sincerity so out of fashion for our time. Over and over, a fascinating bit of drama plays out: after Biss performs a passage to illustrate a point, he turns to the camera, and, visibly shaken by Beethoven, seems for a second unable to speak. When he finally does, the words burst forth in an endearingly awkward way. Jonathan Biss has been waiting his entire life to tell you everything you need to know about Beethoven, and now, momentarily unable to do so, is telegraphing the more important things that still cannot be put into words.