One of the most surprising musical developments is the way quite a few composers have recently rejected atonality and taken up more lyrical tonal idioms, almost as if Bartok and Schoenberg had never existed. If someone had predicted 10 years ago that this would happen, he would probably have had trouble convincing anyone. Our reaction to the 19th century was quite complete by that time. Atonality was the rule, attractive melodies were the exception, and that harsh dissonances had not found their way into popular music was regarded simply as a lamentable example of how popular music was always so far behind art music. Even conservative composers, say Leonard Bernstein or Virgil Thomson, put in a dissonant chord now and then in order to make their work acceptable to a symphony orchestra.

Perhaps now things are swinging back the other way. Terry Riley’s music, at least, is not only tonal, but it can ripple along on one simple diatonic scale for 30 or 40 minutes at a time, with many lovely melodies and no harsh sounds anywhere. The irony, of course, is that Riley is generally regarded as a radical, though it might make better historical sense to consider him an arch conservative.

Riley has been living in San Francisco recently, where he has been devoting most of his time to the study of Indian Music, but he returned to New York for a concert at the Whitney Museum on April 5. He is rather well known now, due to the Columbia recordings of ‘In C,’ ‘Rainbow in Curved Air,’ and ‘Poppy Nogood and the Phantom Band,’ and the Whitney was packed for the occasion. The concert, billed as ‘Music from the Persian Surgery Dervishes,’ was performed by Riley alone, playing a two-manual electric organ, with a delay mechanism to give the instrument a more sustained quality.

Like the music on his albums, the concert was an extremely attractive blend of Oriental modes and repetitive figurations, with a few hints at the composer’s jazz background. The music hovered around one dynamic level for the entire evening, but the thematic material shifted frequently and the interest never lagged. Particularly engaging were the many intricate rhythms which played against each other constantly. Riley is extremely dexterous in this regard, sometimes maintaining a five/four rhythm in the left hand, while shifting curiously between several other meters in his right hand, without ever missing a beat. There were more subtle things too, as when a simple oom-pah figure would gradually turn into a pah-oom figure.

Since this music is largely improvised, it does not have the intellectual depth of the more calculated new pieces by Riley’s former colleagues, Phil Glass and Steve Reich, but it has a warmth and personal lyricism which is quite enticing and accessible. In a way, Riley forms a bridge between the tighter forms of hypnotic music and the looser forms of jazz and raga improvisation.