Henri Dutilleux's small but important output demonstrates a remarkable originality of form and technique. Completed in 1985, Dutilleux's violin concerto L'arbre des songes ("The Tree of Dreams") is the culmination of his experiments in unifying large-scale works. The process of unification is present on two interrelated levels: form and thematic development.
In his notes to this composition, Dutilleux explains that the convention of dividing a work into movements separated by pauses often has the effect of impairing the power of enchantement. In his Tout un monde lointain (1970), Dutilleux subtly delimited the five connected movements by brief moments of repose. This idea was modified in his string quartet Ainsi la nuit (1976), which is configured in seven parts separated from each other by short sections that the composer described as "parentheses" serving either as transitions to new ideas or meditations on preceding ones. In L'arbre des songes, the three parenthetical sections -- explicitly identified in the score as "interludes" -- are given far greater importance as demarcation points of the four actual "movements."
Dutilleux was fascinated with the organic equilibrium, in music, attained when a set of variations follows a theme and then returns to it. It should be pointed out that the second statement of the theme is not (superficial impressions notwithstanding) a literal replication of the initial idea. The difference between the theme and its re-statement is defined by the intervening transformations. This insight influenced Dutilleux's manner of presenting and developing thematic material. Rarely does he present a fixed initial idea which is subsequently developed. Instead, he intentionally blurs the distinction between a theme and its transformations, so that one can only identify the contours of an idea as it gradually emerges throughout the a work. The effect is analagous to the experience of hearing a set of variations without first having heard the initial statement of the theme. Dutilleux explained that this process of continual growth and renewal is at the heart of L'arbe: "All in all the piece grows somewhat like a tree, for the constant multiplication and renewal of its branches is the lyrical essence of the tree. This symbolic image, as well as the notion of a seasonal cycle, inspired my choice of 'L'arbre des songes' as the title of the piece."