Le Soleil des eaux (The Sun of Waters) is a two-movement cantata for soprano, choir and orchestra by Pierre Boulez, based on two poems by René Char, and having a total duration of about nine minutes.

[13] The setting of the poem is unaccompanied; according to Boulez, he conceived of it as a monody and "thought it would be interesting, rather than trying to find an accompaniment, to articulate it by means of interjections, reflections, landscapes, and distorted images.

[4] Regarding the two poems on which Le Soleil des eaux is based, Boulez, in an interview, stated: "these two particular texts represent a somewhat free-and-easy version of anguish and violence, and even of the formal discipline of language.

"[17] He also drew attention to a quotation from Char included in the preface to the score: We have within us, on our temperate side, a series of songs by which we are flanked, wings by which are linked our restful breathing and mightiest fevers.

[18] The first movement, "La complainte du lézard amoureux", consists mainly of lyrical, delicate, quasi-improvisatory vocal solos interleaved with shimmering, colorful orchestral commentaries.

[19] "La Sorgue", the second movement, provides a dramatic, at times violent contrast with the first, and is dominated by the chorus, which hums, speaks, shouts, and sings in an incantatory way, with several short interventions by the soprano soloist.

[8] In a review of the third version of Le Soleil des eaux G. W. Hopkins called the work "enchanting" and "one of Boulez's most accessible scores", praising the composer's setting of the poems and noting the influence of Debussy, Webern, and Messiaen.

"[23] Paul Griffiths wrote that, along with the Second Piano Sonata, Le Soleil des eaux marked "the end of a period in which Boulez, still only twenty-three, had proved he could master and bring together everything he chose to learn from his predecessors".

[24] Robert Piencikowski wrote that the multiple iterations of the score over roughly twenty years are an example of what he calls "revisionitis", in which "one could speak of successive distinct versions, each one presenting a particular state of the musical material, without the successor invalidating the previous one or vice versa.

"[27] Joan Peyser called the piece "powerful and exciting", and wrote: Both the words and music of Le Soleil des Eaux suggest that Boulez would have preferred to emerge from the womb full grown without the years of immaturity during which he felt impotent against a formidable world.