According to The New Penguin Dictionary of Music, Luciano Berio is an Italian composer, pupil of Dallapiccola; has employed spatial effects, e.g. in "Circles" (text by E.E. Cummings) for voice, harp, and 2 percussion; has also written electronic music, and works allowing free choice by performers. A series of pieces each called "Sequence" (sequenza) is for different solo instruments - no. 5 for trombone, no. 6 for viola. His Sinfonia (orchestra, organ, piano, harpsichord, chorus, reciters) incorporates a section of Mahler's symphony no. 2.
Frans Brüggen in an article on Berio's Gesti in "The Recorder and Music Magazine" (November 1966) also says that "Gesti" can be thought of as a little sequenza.
Personal Remarks
I have heard Michala Petri playing "Gesti" sometime in 1982/3. Unfortunately I cannot say that I particularly enjoyed it (perhaps I am simply too old-fashioned in my taste). I find it interesting that although both Frans Brüggen and Michala Petri have broadcast it and given public performances, neither, as far as I know have actually recorded it.

Recorder Sheet Music

Gesti: Recorder Solo (A(T)) Publisher: Universal Edition (UE015627)