Oxymoron collects four works written between 1990 and 2005 by the Estonian composer Erkki-Sven Tüür. Each is for a different line-up: male choir and ensemble, marimba and orchestra, cello and piano, and large ensemble. The title, a figure of speech that joins contradictory terms, fits music that sets apparently unrelated idioms side by side and holds them in a firm architecture. It was the fourth ECM release devoted entirely to his music.

The concerto Ardor was recorded in March 2003 at the Estonia Concert Hall in Tallinn. It features its dedicatee, the percussionist Pedro Carneiro, with the Estonian National Symphony Orchestra conducted by Olari Elts, in a production by Estonian Radio. The other three works date from June 2006. Elts leads the male voices of Vox Clamantis and members of the NYYD Ensemble in Salve Regina and the title piece. Cellist Leho Karin and pianist Marrit Gerretz-Traksmann play Dedication. Manfred Eicher was executive producer.

The booklet describes the method Tüür calls "vectorial writing" and notes that all four works gravitate around the pitch C. Salve Regina (2005) sets a plainchant-like tenor line against hand drum, positive organ and dissonant clusters, and moves like a slow procession that ends on a soft bass drum stroke. Ardor (2001/02) is in three movements: a slow introduction opening into an energetic main section, a static nocturne and a brilliant toccata. The title piece, subtitled Music for Tirol (2003), was commissioned by the Austrian town of Schwaz and draws partly on the Alpine landscape. Dedication (1990), the oldest work here, is an elegy for cello and piano written in memory of Kuldar Sink, its contrasting sections divided by brief pauses for breath.

Guy Rickards in Gramophone found Ardor "varied and evocative, full of fascinating sonorities", and praised the soloist's authority and virtuosity. He heard the disc as a portrait of the composer in his latest phase. In International Record Review, Martin Anderson noted the density of the writing but concluded: "If you don't yet know his music, here's a fine place to start." Hubert Culot of MusicWeb International was more reserved about the title piece, which he found rambling at times.

CD edition, ECM New Series 1919, released in March 2007, with notes by Tüür and Hans-Klaus Jungheinrich.