Ayreon ( ) is a project by Dutch composer and musician Arjen Anthony Lucassen.

Ayreon's musical style derives mostly from heavy metal and progressive rock, but combines them with genres like folk, classical and electronica to form what some call a completely new style of music. The majority of Ayreon's albums are dubbed "rock operas" due to the fact that the albums contain complex storylines featuring a host of characters, each represented by a unique vocalist.

Ayreon's music is characterized by the use of traditional instruments in rock music (guitars, bass guitar, drums, synthesizers, electric organs) mixed with instruments more native to folk and classical music (i.e. mandolins, violins, violas, celli, flutes, sitars and didgeridoo). Lucassen writes the music and the lyrics, sings and plays instruments on all of the Ayreon albums, alongside many guest musicians.

Ayreon is the brainchild of Arjen Anthony Lucassen , a dutch musician who writes and records virtually all of his music himself, employing only a drummer, several vocalists and sometimes some wind-instrumentalists for his albums. Ayreon releases are almost always rock-operas with a common, science fiction style storyline, although there have been exceptions in the form of Actual Fantasy (not a rock opera) and The Human Equation (not science fiction, but still the same storyline) Though many beli