The bassoon is a double reed instrument, like the oboe, but with a lower and reedier tone. Music for the bassoon is mostly written in the bass clef, with most of its notes below Middle C. The range of a bassoon is approximately 3 octaves, ranging from B flat (2 octaves below Middle C) to C (1 octave above Middle C). It is approximately 4' 6" in length.
The contrabassoon, or double bassoon is even larger and lower in pitch. Its range is exactly one octave below the bassoon, but is written in the same range, thus making it a transposing instrument. (See Oboe family.)
The bassoon, also known as "fagotto" in Italian, is a highly versatile and agile instrument despite its large size. Its low notes can "speak" clearly and quickly, making it a good compliment to other bass instruments in orchestral scoring, where it often shares the same part as the cello.
Some famous pieces containing prominent bassoon parts include: "Peter and the Wolf", by Sergei Prokofiev and Paul Dukas' Sorcerer's Apprentice (which also has solo passages for contrabassoon). Concertos have also been written for it, the most famous being by Mozart, but also by Carl Maria von Weber, Vivaldi (who wrote 37!), Johann Nepomuk Hummel, and Franz Danzi. Igor Stravinsky also opened his famous ballet Le Sacre du Printemps with an exposed bassoon solo in its highest register, causing it to be mistaken for a saxophone in its first performance.
Some notable bassoonists include William Waterhouse and Arthur Weisberg.