Hollywood sound designer and film editor Walter Murch nominates Symphonie pour un homme seul by Pierre Schaeffer and Pierre Henry, music he first heard on the radio as a schoolboy and which influenced his subsequent work in the field of film sound. Author and journalist Rob Young puts the work in the context of post-war Paris and Schaeffer’s early experiments at French Radio which led to the birth of musique concrete.

Composer Nico Muhly nominates Philip Glass's Music in Twelve Parts, a large-scale set of pieces for electric organs, voice, flutes and saxophones which is considered to be an early masterpiece of the New York minimalist. Gillian Moore puts the work in context and suggests how this numerical process music attains its human quality through the choice of sounds.

Writer and critic Paul Driver explains why Maxwell Davies’s 8 Songs For A Mad King is so uniquely important in the development of music theatre; and the Viennese composer and chansonnier HK Gruber describes the work from the inside, as a performer who has sung the taxing part of the King many times.

Violinist David Harrington celebrates George Crumb's groundbreaking 1970 work for electric string quartet, Black Angels - the work which inspired him to form the Kronos Quartet. Gillian Moore puts the piece in context, as a work full of dark foreboding and extreme sounds, in direct reaction to the Vietnam War.

Composer Anna Meredith nominates Gerald Barry's "bold and daring" Piano Quartet No.1, with commentary from an established interpreter of Barry's music, conductor Richard Baker.

Writer and musician David Toop celebrates Toru Takemitsu's soundtrack for Masaki Kobayashi's 1964 chiller Kwaidan, based on Lefcadio Hearn's retelling of Japanese ghost stories; film scholar Peter Grilli describes how the composer worked closely with the director and recording technicians to create a soundworld that was integral to the drama of the film.

Theatre director Katie Mitchell describes her first encounter with the music of Italian composer Luigi Nono and her subsequent staging of Al gran sole carico d'amore, an operatic work which interweaves stories from the 1871 Paris Commune and the Russian Revolution. Conductor Richard Bernas highlights the lyrical and communicative aspects of Nono's music and its place in the world of post-war serialism.

Jazz pianist Ethan Iverson nominates Milton Babbitt's Philomel for soprano and tape, "a classic record that should be owned by all fans of the avant-garde"; Paul Griffiths explains how Babbitt used the timbral and rhythmic resources of the Mark II RCA Sound Synthesizer to help realise his own brand of twelve-tone music. And we hear the voice of the composer himself from recordings made by the BBC in the 1960s.

Film director Barrie Gavin selects Jonathan Harvey's Mortuos Plango, Vivos Voco, an electroacoustic piece made from the sound of the largest bell at Winchester Cathedral and the voice of the composer's chorister son. Commentator Gillian Moore describes how Harvey used technology at IRCAM in Paris to manipulate and integrate these two sounds, and we hear from Harvey himself on the significance of the bell's inscription and the qualities of its tonal spectrum.

Finnish conductor and music director of Ensemble InterContemporain Susanna Malkki pays tribute to Stockhausen's 1950s masterpiece Gruppen for 3 orchestras, and highlights some of the challenges to conductors in performing it; commentator Paul Griffiths places the work in the context of Stockhausen's early output, and explains how the shape of a mountain view in Switzerland dictated the work's tempo patterns.

Conductor Richard Bernas recalls his momentous first encounter with Berio's Sinfonia, a work which reflected and commented on the events of its time, from the Paris riots to the assassination of Martin Luther King, and whose third movement is an extraordinary assemblage of musical and literary quotations. Commentator Gillian Moore explains the significance of the texts which include Levi-Strauss's Le Cru et le cuit and Samuel Beckett's The Unnamable; and we hear from the composer himself,...

Roxanna Panufnik nominates Arvo Part's Cantus In Memoriam Benjamin Britten, "beautifully simple and spiritual" music that she feels a strong connection to; while Paul Griffiths tells of Part's early struggle to find his own voice in Soviet Estonia and subsequent breakthrough with a radical new style he called Tintinnabuli.

Howard Skempton singles out Extensions 3 by the American composer Morton Feldman, a piece he found "liberating, inspiring, and radically different". Paul Griffiths places the work in Feldman's early output and highlights the challenges to performers of music which is both very slow and very quiet. Plus excerpts from a BBC archive interview in which Feldman himself describes his approach to composition.

Stephen Fry describes his delight and bewilderment at first hearing Conlon Nancarrow's Study No. 21 - also known as Canon X - for player piano. Nancarrow devoted his composing life to creating futuristic canonic studies for his custom-altered 1920s Ampico instrument, combining elements of jazz, Bach and Stravinsky, as we hear from the other voice in this episode, pianist Joanna MacGregor.

Percussionist Steven Schick recalls how a chance meeting with Brian Ferneyhough led to the commission of Bone Alphabet, the composer's only piece for non-pitched instruments; and writer Paul Griffiths describes the work's physicality and rhythmic complexity.

Artist Tom Phillips on Howard Skempton's Lento for orchestra, a completely tonal piece that he admires for achieving "content with simplicity"; Gillian Moore puts it in the context of the English experimentalist tradition; and the composer himself explains in detail the process by which he developed his initial sketches into the finished work.

Composer and former Battles frontman Tyondai Braxton nominates Poeme electronique by Edgard Varese, whose soundworld has been a continuing influence on his own work; while Gillian Moore tells the story of Varese's long struggle to create a futuristic music that he finally achieved in this piece, composed for an array of hundreds of loudspeakers inside the Le Corbusier-designed Philips Pavilion at the 1958 Brussels World Fair.

Artist Tacita Dean on John Cage's legendary 4'33" and how it provided an inspiration for Stillness, her 2007 project with choreographer Merce Cunningham. Conductor and Cage collaborator Richard Bernas underlines some important but often neglected aspects of the score and draws a parallel with the visual arts scene of 1950s New York. And we hear the voice of the composer himself from a 1970s BBC interview with critic Frank Kermode.

Pianist and Scratch Orchestra member John Tilbury speaks up for The Great Learning by the radical British composer and political activist Cornelius Cardew. Paul Griffiths explains its place in Cardew's musical and political thinking, and the composer suggests musicians abandon ‘individual choice’ and join together to orchestrate social change.

Mathematician Marcus du Sautoy explains how Iannis Xenakis uses the symmetry of a cube to determine musical parameters in Nomos Alpha for solo cello; Paul Griffiths highlights the composer's innovations in the fields of sound and instrumental writing; and we hear an archive interview in which Xenakis credits his teacher Olivier Messiaen in helping him to find his own compositional voice.

Dutch composer Michel van der Aa salutes compatriot Louis Andriessen's 1976 work for amplified voices and large ensemble, De Staat. Gillian Moore highlights the modern scoring of the work, informed as much by rock music as Stravinsky, while the composer himself reveals how a recording of a Javanese women's choir fed directly into the soundworld of this powerful setting of a text from Plato's Republic.

Sir Harrison Birtwistle singles out Pierre Boulez's 1950s cycle for voice and mixed ensemble, and describes encountering the score for the first time, while Paul Griffiths explains how the composer employed total serialism and a radical new approach to instrumentation in illuminating the fleeting, surrealist poetry of Rene Char.

Novelist and poet Mark Haddon explains what it is about Elliott Carter's String Quartet No.3 that reminds him of an argumentative family meal; the composer himself describes with relish his 'eclipses' of sound; and Paul Griffiths explains Carter's use of metric modulation.

Film-maker Sophie Fiennes explains why she chose György Ligeti's Atmosphères for the soundtrack of a film about artist Anselm Kiefer, and Paul Griffiths explains its significance in Ligeti's development of cloud-like musical structures. And we also hear from the composer himself.

Matthew Herbert, songwriter and electronic music producer, reflects on the continuing relevance of Steve Reich's seminal 1988 piece for string quartet and tape, where recorded speech leads the melodic lines to create a remarkable and evocative atmosphere. The feature includes commentary from the South Bank's Head of Contemporary Culture Gillian Moore, and we also hear the voice of the composer himself.