The composer Klas Torstensson (b.1951) studied composition at the Ingesunds Musikhögskola, musicology at the University of Gothenburg and electronic music at the Institute of Sonology, Utrecht. His compositions are performed by orchestras, ensembles and soloists worldwide.

Urban Songs for soprano Charlotte Riedijk, Ensemble Intercontemporain and computers, commissioned by Ircam, Paris, was premiered in 1992, and was thereafter programmed for another two seasons by the same ensemble, as well as by many other European ensembles, such as Ensemble Modern (Frankfurt), Asko Ensemble (Amsterdam) and KammarensembleN (Stockholm).

In 1994, Torstensson composed The Last Diary for speaking voice and large ensemble, based on the diaries of S.A.Andrées, leader of the tragic Arctic balloon expedition of 1897. The Last Diary has in the past decade also been translated into German - for performances in Vienna and Graz with H.K.Gruber in the role of Andrée - and Icelandic.  

The same material served as a basis for his opera The Expedition (1994-1999) for soloists, orchestra and (live) electronics, to a libretto written by the composer.

The opera was premiered in concert form during the 1999 Holland Festival in the Amsterdam Concertgebouw, in a performance conducted by Peter Eötvös. Performances followed in Germany, Sweden and Norway.

1999-2002 Torstensson wrote a full-length cycle entitled Lantern Lectures. The cycle was a joint commission by Le Nouvel Ensemble Modern (Montréal), Asko Ensemble (Amsterdam), KammarensembleN (Stockholm), Klangforum Wien and Oslo Sinfonietta. Over the years 2000-2004 Lantern Lectures was performed twenty-seven times, by seven ensembles in thirteen countries.

In October 2004, the song cycle In großer Sehnsucht (with texts by five 'tragic' women: Camille Claudel, Frida Kahlo, Cristina di Svezia, Rosa Luxemburg   and Louise Michel) received its first performance in the Concertgebouw Amsterdam, by Charlotte Riedijk and the Osiris Piano Trio.

Torstenssons music has been presented on most major European new music festivals. He has also been featured composer at festivals such as Stockholm New Music 1999 (together with Mauricio Kagel and György Kurtág), Time of Music 2001, Viitasaari, Finland, and Montréal-Nouvelles-Musiques 2003.

In 1991 Torstensson received the Matthijs Vermeulen Prize - the most prestigious composition prize in The Netherlands, followed by the 'Stora Christ Johnson Priset', the major Swedish composition prize awarded to him by the Swedish Royal Music Academy in 1999.

Most of Torstensson's music is available on CD.