Ligeti only wrote two string quartets in his lifetime (regrettably), but both are superb examples of the form, in which the composer's unique synthesis of atonal and lyrical elements are on full and glorious display. The First String Quartet was written in 1953-54, when Ligeti's musical language was still evolving, and is unsurprisingly more traditional in form. Yet even at this early stage, his work betrayed his experimental nature. The melodic line, while highly accessible, proceeds in nervous, jagged fashion, engaging the listener emotionally while keeping him or her off balance intellectually. This characteristic duality would become more pronounced as Ligeti's art matured. The four movements alternate between moments of almost frenzied atonality with passages of heartbreaking lyricism and stillness. Also noteworthy is how Ligeti concentrates on the sound of each instrument, making the distinct tonal textures of violin, viola and cello integral elements of the musical narrative. The Second String Quartet is a much different and far more formidable animal, foregrounding the radical abstraction of its harmonic and rhythmic contours. A pronounced sense of restlessness and foreboding pervades the first four movements, with the threat (or promise) of a violent explosion at any moment. The writing has a muscular, at times brutal power. Yet for all its fierce experimentation, it's no less accessible than Ligeti's earlier, more conventional quartet, and the beatific serenity of the last movement is one of the most moving, if enigmatic, five minutes of music you're likely to come across.