An etude (French: étude, “study”) is a form of musical composition originally intended to aid or improve the technique of the player. As the Italian studio, there are examples of the form dating back to the first half of the 18th century. With the development of the modern piano in the early 19th century, and its growing popularity as a household instrument, books of etudes appeared containing pieces, each of which instructed on a particular facet of technique.
Frédéric Chopin’s two sets of etudes (Opp. 10 and 25, published in 1833 and 1837) marked the first appearance of the genre in the concert hall, and are also the most frequently performed today. By Chopin's admission, pianistic wizard Franz Liszt was the first to truly master these etudes. A student of Czerny, Liszt had earlier written a modest set of finger-exercises himself entitled Études en 12 exercises in about 1827, which stylistically resemble those of his teacher; after two miraculous transformations in 1837 and 1851, these pieces were to finally become the Études d’exécution transcendante – or “Transcendental studies” - among the most difficult to play of all piano works. A similar transformation happened with Liszt's so-called "Grand Etudes After Paganini," written in honor of one of the greatest violin virtuosi in history, which contains the popular "La Campanella." Of the various other sets of studies written for the piano, those of Claude Debussy, Sergei Rachmaninoff, and Alexander Scriabin have the most lasting popularity, although Alkan, Saint-Saens, Prokofiev, Ligeti and Martinu have also added to the repertoire.
Other composers, such as Robert Schumann and Johannes Brahms, who shied away from writing unabashed concert etudes, expressed their fascination with piano technique through hybrid-works. Schumann began his "Symphonic Etudes" (Op. 13) in 1834 under the inspiration of Chopin's Op. 10, and envisioned the work originally along these lines. What eventually came of the effort however was a half-hour long masterful set of variations, of which some were labelled "etude" and others merely "variation." In 1862 Brahms authored two sets of variations after Paganini (Op. 35) which were subtitled "Studies for pianoforte," and not without reason - their nearly intractable difficulties led Clara Schumann, one of the great pianists of her age, to curse them under the moniker "Witch variations." Brahms also "fiddled" with the works of others, for example turning one of Schubert's Op. 90 Impromptus into a "Study for the left hand". Also for the left hand only is the sublime arrangement of a Bach chaconne that ends his "Five Piano Studies" on works by Chopin, Weber and Bach.
Early books of studies for the violin and for the guitarare as old as those for the piano. (The Spanish composer and virtuoso guitarist, Fernando Sor, wrote many dozens of studies for the guitar in the early 19th century, many of which are recital pieces today but were originally intended for instruction.) The repertoires of various other instruments have been enriched by the form - examples include six "Tango Etudes" for solo flute by Astor Piazzolla - for voice: Maurice Ravel wrote a piece for soprano; "Vocalise-etude en forme de habanera" - and even for full orchestra: Igor Stravinsky’s “Four Studies for Orchestra” and Alan Rawsthorne’s “Symphonic Studies” are notable.