Of all the works of Wolfgang Amadeus Mozart, the most characteristic are his 27 concertos for piano and orchestra. Every one from no.9 onwards (K271) is frequently heard in the concert hall. Mozart was himself a virtuoso concert pianist. His dramatic gifts, shown in the great operas such as The Marriage of Figaro and The Magic Flute, were ideally attuned to the concerto, a genre in which the more epic manner of Joseph Haydn fared less spectacularly.

The first four concertos in the series are arrangements of other very early works for solo piano and introduce no original material. The next four concertos are among the more attractive works of Mozart's youth. Concerto no.5 in D (K175), which he composed in 1773 at the age of 17, has an ambitious fugal finale, while no.6 in B flat (K236) ends with a catchy gavotte-like 'rondeau'. Concerto no.7 in F (K242), for three pianos, is a less serious piece. Composed for a countess and her two daughters, the piano parts are of varying difficulty.

Composed in the month that Mozart turned 21, concerto no.9 in E Flat (K271) is a watershed in his career and is the first big concerto in the mature classical style by any composer. Especially noticeable is the new scale and dramatic pacing of the imposing opening movement; the piano takes the stage from the very beginning with a personality of its own, like a character in an opera. The second (slow) movement draws from the same inspiration, in the form of a tragic recitative.

Concerto no.9 is called the 'Jeunehomme' after the name of the visiting virtuoso for whom Mozart composed it. As well as the concerto for Mme Jeunehomme, Mozart composed three other concertos for players other than himself: no.14 in E Flat (K449), an original work with a strong personality, was written for his pupil Babette Ployer, as was the popular no.17 in G (K453); and no.18 in B Flat (K456), notable for its melancholy andante theme and variations, which was written for a blind composer and performer, Maria Theresia von Paradis. The other concertos he wrote for himself to perform at his subscription concerts in Vienna.

While still in Salzburg, however, Mozart wrote a concerto for two pianos and orchestra, no.10 in E Flat (K365). A magnificent piece of music in a light-hearted vein with a stately introduction, this concerto has retained its popularity. The merry finale is a sure-fire hit in the concert hall and is sometimes played by itself as a display piece.

Mozart moved from Salzburg to Vienna in 1782, where he married Constanze Weber. That year he composed three concertos, among them the engaging no.12 in A major (K414). Sometimes performed in a chamber version it begins with a tuneful allegro with mock-military fanfares, while the finale is a pointed allegretto, well calculated to bring down the house.

The greatest concertos were composed from 1784 onwards. Favourites from among these are no.15 in B Flat (K450), with its 'hunting' finale, and no.17 in G (K453), with its wonderfully graceful opening movement, full of harmonic adventure. No.19 in F (K459) has what is sometimes referred to as the greatest finale of the whole series, a dizzying display of symphony, fugue and concerto rolled into one. Interestingly, nos.16, 17, 18 and 19 all begin with the same dotted rhythm, yet the ensuing music in each case is worlds apart.

The two concertos composed in a minor key, no.20 in D minor (K466) and no.24 in C minor (K491) display the so-called 'daemonic' side of Mozart's genius. No.20 is overtly dramatic, as if pitting the piano against the orchestra, while no.24 is more inward-looking; its huge opening movement (it has a double exposition for orchestra alone, before the piano comes in) has a subdued, threatening atmosphere far removed from the fireworks of the D minor. Beethoven admired both of these concertos and wrote cadenzas for K466.

One of Mozart's best known compositions is the slow movement of no.21 in C (K467). The piano is the soloist in an spellbinding 'aria without words', its cantilena melody accompanied by softly pulsating chords. It has become well known as the music used for the film Elvira Madigan. The slow movements of nos.22 and 23 (K482 in E Flat and K488 in A) are both poignant pieces in minor keys, the latter perhaps more deeply felt. The E Flat concerto, the longest and most leisurely of the series, also has an extra movement (a minuet) inserted into its galloping finale.

Composed in 1786, concerto no.25 in C (K503) is the one of the grandest of the series, especially in its towering first movement, marked Allegro Maestoso. Beethoven's fourth piano concerto in G echoes its characteristic four note motif (it also recalls the rhythm of the opening call of Beethoven's fifth symphony). It is the last of the great series of piano concertos composed from 1784 to 1786.

Two more piano concertos were to be written. The first was composed in 1788: no.26 in D major (K537). Written in what appears to be a precursor of the (technically) more relaxed romantic style, it has the sobriquet of 'Coronation', as it was played, together with no.19, at the festivities to celebrate the coronation of the Emperor Leopold II.

One of the most popular concertos is the final one, no.27 in B Flat (K595), written in 1790. The opening movement, after a muted introduction, gives the impression of endless melody. Mozart's late style is at its most ethereal in the autumnal slow movement and the finale manages to sound both cheerful and wistful. The cumulative effect is among the most nostalgic in all art. A listener might be moved to tears, but not for sorrow.