It may be objected that the title contains a contradiction in terms. For how is it that a movement can be at once a fantasy whose essence is that of a free design drawn according to the whim of the composer, and a sonata which is essentially a formal construction on lines laid down by authority and held by tradition? The fantasy submits to no authority other than that of each individual composer, an authority therefore of mere personal preference having so little status beyond the confines of a single work as to lack the accepted attributes of authority. Tradition the fantasy has, going back to the fantasia or in this country to the Tudor fancy; it is a tradition of free-thinking, regulated by no rigid formalities of construction, the result of individual thought-processes which have to impose themselves on the listener through an inherent rightness and cogency. Yet this is also the very essence of symphonic writing, this ability to think cogently and so compel the listener first to compliance and thence to understanding. And since the fantasy possesses this as its main characteristic it at once comes in contact with symphony and sonata.