Gustav Holst was an English composer of choral, orchestral, wind ensemble, and chamber works.
Holst was also an avid music educator and conductor, and was master of music at the St. Paul Girl's school in Hammersmith, London. I first heard of Gustav Holst my sophomore year in high school band when we rehearsed and performed Suite in Eb for Military Band. It has remained one of my most favorite wind ensemble pieces to perform and listen to. I have also had the pleasure of performing wind ensemble arrangements of Mars and Jupiter, two movements from Holst's most famous (though one of his personal least favorites) work The Planets. The drama and intensity of emotions in both pieces is astounding not only to the performer, but to the listener as well. The Planets has been widely performed by orchestras all over the world, and remains a prominent work in the orchestral world.
Holst was very interested in old English folk songs. In his works he has adapted and incorporated various folk songs. This is true in movement four of Second Suite in F for Military Band, Fantasia on the Dargason (which was also adapted into a string quartet). As the main dance melody is being passed around the woodwinds, the brass section is heard playing Greensleeves, and the mix of the two melodies is clever.
http://www.gustavholst.info/ - This is an informative website with a comprehensive biography, catalog of Holst's music, and journals written by scholars about Holst's compositions.
http://www.youtube.com/watch?v=ngTnToAs4uU - This is a video of Holst's First Suite in Eb for Military Band. It is one of the corner stones of wind ensemble literature and one of my favorite pieces of all time.
http://www.suite101.com/content/gustav-holst---the-planets--a6062 - This is a short essay on Holst's most popular suite, The Planets.