Ludwig van Beethoven wrote his 32 piano sonatas between 1795 and 1822. Although originally not intended to be a meaningful whole, as a set they compose one of the most important collections of works in the history of music.^[1] Hans von Bülow called them "The New Testament" of the piano literature (Johann Sebastian Bach's The Well-Tempered Clavier being "The Old Testament").^[2]

Beethoven's piano sonatas came to be seen as the first cycle of major piano pieces suited to concert hall performance.^[1] Being suitable for both private and public performance, Beethoven's sonatas form "a bridge between the worlds of the salon and the concert hall".^[1] The first person to play them all in a single concert cycle was Hans von Bülow, the first complete recording is Artur Schnabel's for the label His Master's Voice.

Beethoven's early sonatas were highly influenced by those of Haydn and Mozart. Even so, he began to find new ways of composing his sonatas. His Piano Sonatas No. 1, 2, 3, 4, 7, 11, 12, 13, and 15 were four movements long, which was rather uncommon in his time.

After he wrote his first 15 sonatas, he wrote to Wenzel Krumpholz, "From now on, I'm going to take a new path." Beethoven's sonatas from this period are very different from his earlier ones. His experimentation in modifications to the common sonata form of Haydn and Mozart became more daring, as did the depth of expression. Most Romantic period sonatas were highly influenced by those of Beethoven. After 1804, Beethoven ceased publishing sonatas in sets and only composed them as a single opus. It is unclear why he did so.

Beethoven's late sonatas were some of his most difficult works and some of today's most difficult repertoire. Yet again, his music found a new path, often incorporating fugal technique and displaying radical departure from conventional sonata form. The "Hammerklavier" was deemed to be Beethoven's most difficult sonata yet. In fact, it was considered unplayable until almost 15 years later, when Liszt played it in a concert.

In a single concert cycle, the whole 32 sonatas were first performed by Hans von Bülow.^[3] A number of other pianists have emulated this feat, including Artur Schnabel (the first since Bülow to play the complete cycle in concert from memory), Roger Woodward^[4] and Michael Houstoun, who has performed the full sonata cycle twice; first at the age of 40, and then 20 years later in 2013.^[5] Claudio Arrau, Alfred Brendel and Maurizio Pollini performed the cycle several times.^[6] Daniel Barenboim has performed the complete cycle many times in cities around the globe, including Tel Aviv, Vienna, Berlin, Paris, Prague, New York, and his hometown of Buenos Aires.

The first pianist to make a complete recording was Artur Schnabel, who recorded them for the British recording label His Master's Voice (HMV) between 1932 and 1935.^[7][8][9] Other pianists to make complete recordings include Claudio Arrau,^[10] Vladimir Ashkenazy, Wilhelm Backhaus, Daniel Barenboim (twice: for EMI and Deutsche Grammophon), Malcolm Binns and Ronald Brautigam (on period pianos), Alfred Brendel (three times: once for Vox and twice for Philips, 1970-77 and 1992-96), Paul Badura-Skoda, Rudolf Buchbinder, John O'Conor, Annie Fischer, Claude Frank, Richard Goode, Maria Grinberg, Friedrich Gulda, Jenő Jandó, Wilhelm Kempff (twice, in mono and stereo for Deutsche Grammophon), Stephen Kovacevich, Mari Kodama, Anton Kuerti, Paul Lewis, HJ Lim, Louis Lortie, Kun-Woo Paik, Alfredo Perl, Maurizio Pollini, Bernard Roberts, András Schiff, Russell Sherman, Robert Taub, and Gerard Willems.

Known for their Beethoven, both Solomon and Emil Gilels began recordings of the sonatas, but neither completed the set. Whereas Solomon suffered a career-ending stroke, Gilels died in 1985 before he could finish his own set.

Glenn Gould, Sviatoslav Richter, and Rudolf Serkin recorded selected sonatas, but never recorded the complete series.

The Op. 106 sonata was orchestrated by Felix Weingartner for a Romantic era orchestra.