It was because the ebb of rhythmic invention was comparatively low in late-nineteenth-century European music that Stravinsky was able to apply what I once termed “a rhythmic hypodermic” to Western music. His shocker of 1913, The Rite of Spring, a veritable rhythmic monstrosity to its first hearers, has now become a standard item of the concert repertory. This indicates the progress that has been made in the comprehension and enjoyment of rhythmic complexities that nonplused our grandfathers. And the end is by no means in sight. Younger composers have taken us to the very limit of what the human hand can perform and have gone even beyond what the human ear can grasp in rhythmic differentiation. Sad to say, there is a limit, dictated by what nature has supplied us with in the way of listening equipment. But within those limits there are large areas of rhythmic life still to be explored, rhythmic forms never dreamed of by composers of the march or the mazurca.

In so saying I do not mean to minimize the rhythmic ingenuities of past eras. The wonderfully subtle rhythms of the anonymous composers of the late fourteenth century, only recently deciphered; the delicate shadings of oriental rhythms; the carefully contrived speech-based rhythms of the composers of Tudor England; and, bringing things closer to home, the improvised wildness of jazz-inspired rhythms — all these and many more must be rated, certainly, as prime musical pleasures.

Tone color is another basic element in music that may be enjoyed on various levels of perception from the most naive to the most cultivated. Even children have no difficulty in recognizing the difference between the tonal profile of a flute and a trombone. The color of certain instruments holds an especial attraction for certain people. I myself have always had a weakness for the sound of eight French horns playing in unison. Their rich, golden, legendary sonority transports me. Some present-day European composers seem to be having a belated love affair with the vibraphone. An infinitude of possible color combinations is available when instruments are mixed, especially when combined in that wonderful contraption, the orchestra of symphonic proportions. The art of orchestration, needless to say, holds endless fascination for the practicing composer, being part science and part inspired guesswork.

As a composer I get great pleasure from cooking up tonal combinations. Over the years I have noted that no element of the composer’s art mystifies the layman more than this ability to conceive mixed instrumental colors. But remember that before we mix them we hear them in terms of their component parts.

If you examine an orchestral score you will note that composers place their instruments on the page in family groups: in reading from top to bottom it is customary to list the woodwinds, the brass, the percussion, and the strings, in that order. Modern orchestral practice often juxtaposes these families one against the other so that their personalities, as families, remain recognizable and distinct. This principle may also be applied to the voice of the single instrument, whose pure color sonority thereby remains clearly identifiable as such. Orchestral know-how consists in keeping the instruments out of each other’s way, so spacing them that they avoid repeating what some other instrument is already doing, at least in the same register, thereby exploiting to the fullest extent the specific color value contributed by each separate instrument or grouped instrumental family.