Canon is a kind of polyphonic music, whose original meaning is "regularity". The same melody appears at different heights such as the same degree or the fifth degree of each voice, resulting in continuous imitation, that is, strict imitation counterpoint. The first voice is called "Qisentence", the repeated voice after one or two bars is called "Yingsentence", and the music written by cannon technique is called "cannon song". The "rotation" in acoustic music is also a kind of "cannon song". Canon appeared in 13 and 4 centuries, and later generations often took ancient songs as canon themes.

Pahaebel was born in Nuremberg, southern Germany on 1653, and died in the same place on 1706. He is an organist and composer in the Baroque period in Germany, and has the reputation of "master of organ music". His greatest contribution in the history of music lies in his creation of fugue music and his efforts to interpret choral variations into keyboard music, which greatly influenced Bach, the "father of music".

The following is taken from the introduction of BMG Records.

Cannon is by far the most popular classical music in the world. Dominate the American billboard pop music charts for more than a hundred weeks, and also refreshed the Beatles' "breaking charts" several times. It's amazing, because many people may not read the title of the song, but they can finish humming the melody. From TV commercials, radio, weddings, funerals and celebrations, tooth extraction, department stores, bookstores, restaurants, cell phone ringtones, and even pop singer Wu's songs, you can hear the sound of "cannon". So classical music is the most popular song that can stand the test of time, but it is absolutely true.

. Canon is only five minutes long. Although it is a beautiful sketch, it will make Pahai Bell famous all his life. If he were still alive, he might be the musician with the highest royalty income in the world. Canon's melody is simple and simple, but it has a precise and perfect music structure, which fully shows the rigor and balance of counterpoint. It is worth mentioning that its bass has only eight notes to form the same melody, which is repeated 28 times from beginning to end. It is not only an attractive song for men, women and children, but also the best introduction to classical music for the first time.