The music of Gustav Holst seems to be rather out of fashion at the moment, and very few of his works - apart from The Planets - feature regularly in concert programmes. This is surprising since Holst, though a composer who reflected the age in which he lived, was a composer very much of our time, too.

His personality was a curious mixture, combining the sociable and outgoing with the introverted and withdrawn. He was a great teacher, not only of music students but also of children and amateurs. He taught at St.Paul's Girls' School in London, and at Morley College, and even trained the church choir at Thaxted in Suffolk for a while. "If a thing is worth doing, it is [even] worth doing badly" he is reported saying - yet he was fastidious in his own scores, reworking and rejecting ideas many times until he was satisfied. He was interested in the avant-garde of his time, admiring the works of Stravinsky and Schoenberg such as The Rite of Spring and Five Orchestral Pieces. However, the frequent use of unusual time signatures (both 'Mars' and 'Neptune' are in 5 beats to the bar) and the dissonances which appear in Holst's scores never sound as harsh as one might expect. He was interested in all sorts of "New Age" mysticism, dabbling in Astrology, which gave him the inspiration for The Planets, and various Eastern philosophies, setting many Sanskrit texts and words from the Rig Veda.

He began work on The Planets in 1913, and only completed orchestration in 1916. The first public performance had to wait until after the war, in 1919, when it was given at the Queen's Hall in London under Adrian Boult - though there had been a professional play-through to an audience of friends and guests the previous year. At one time he thought of calling the work Seven Orchestral Pieces, but the work is more integrated than that title would suggest. Each of the seven movements is like a short tone poem based on one aspect of the supposed character of the planet's influence on man. It is not symphonic but pictorial. And how vivid the pictures are!

Mars is a picture of the utter brutality of modern warfare, and it comes as a shock to realise that the tanks and machine guns, pictured so graphically here, were still in the future. The relentless battering builds up from a quiet but menacing start to a series of terrifying climaxes. Holst uses his very large orchestra to its full power, with dynamic markings of fff and ffff. The close is a series of brutal hammer blows. Holst's predictions were to prove all too true in the following few years.

Venus, by contrast, is pure and peaceful. The four rising French Horn notes which start the movement keep the music feeling lifted and floating throughout. Holst dispenses with the heavy brass and percussion here, using just strings, wind and horns, with occasional comments from the celeste.

Mercury, the Messenger of the Gods, is a swift scherzo, sometimes in two different keys at the same time, and alternating between 3/4 and 6/8 frequently. But the generally thin and quiet textures, and the fast speed impart a feeling almost of a Mendelssohn scherzo. At one point the violins have a very high note repeated in a curious accato rhythm - the Messenger of the Gods clearly communicates in morse code sometimes!

Jupiter brings jollity; a heavily syncopated tune against scurrying quavers, a folk-like tune in triple time, and in the middle section a big, genial, relaxed tune. The setting of this tune as a hymn to patriotic words ("I vow to thee my country") was done later, and brings false associations - try and forget them!

Saturn is the bringer of Old Age, and his heavy tread is frighteningly apparent here. Weariness has never been depicted so well in music, before or since. This was Holst's favourite movement and, he thought, the best one. It builds up steadily as a desolate funeral march to a great climax of tolling bells and displaced rhythms. The movement ends with a peaceful, yet curiously uncomforting, coda.

Uranus, the Magician, clearly went to the same school of magic as the magician in Dukas' Sorcerer's Apprentice. He is powerful, loud and vulgar, and seems to be given to practical jokes.

Neptune is, for me, the most radical of all the movements. In an early work Schoenberg set the words "I feel an air from another planet", and that is what one feels here. It is pianissimo throughout, and towards the end Holst introduces a wordless, disembodied chorus. And at the very end, the chorus float away, oscillating between two chords which gradually fade away into the silence of deep space.