Arjen Anthony Lucassen, Dutch singer-songwriter, guitarist, and producer
Arjen Anthony Lucassen (born 3 April 1960) is a Dutch singer, songwriter, multi-instrumentalist musician and record producer best known for his long-running progressive metal/rock opera project Ayreon. Lucassen started his career in 1980 as the guitarist and backing vocalist of Dutch band Bodine as Iron Anthony, before joining Vengeance in 1984. After eight years he left the band, wanting to go into a more progressive direction, and released two years later an unsuccessful solo album entitled Pools of Sorrow, Waves of Joy under the nickname Anthony.

In 1995, Lucassen released an album uncredited to any artist called Ayreon: The Final Experiment, in which he sang, wrote every song and played most of the instruments. The album conducted to the creation of Ayreon; despite being relatively unknown at first, the project gained notable attention and praise with the release of its third album Into the Electric Castle, establishing Lucassen as a notable composer of rock operas. Following Ayreon's success, Lucassen has been involved in many other projects: he is the creator, composer and current guitarist/keyboardist of Star One, Guilt Machine, and The Gentle Storm, and the creator and former guitarist of Ambeon and Stream of Passion. He composes and writes most of his songs, but leaves the lyrics to his musical partners in some of his projects.

Lucassen plays a wide variety of instruments: his main instruments are guitar and keyboards, however he also plays bass, banjo and many others. Overall, in his career and including all his bands and projects (as principal instrumentalist/creative force or as a member), Lucassen has released twenty-six studio albums, four live albums, two EPs and seventeen singles. He has also made many minor participations alongside various artists including Shadow Gallery, After Forever, Within Temptation and Avantasia, and appears in over 50 albums.

Since the creation of Ayreon, Lucassen progressively made a name for himself under rock and metal reviewers, with many critics calling him a "genius", and praising his composition abilities and originality. In his review of 01011001, AllMusic reviewer Cosmo Lee stated "Music this over the top almost defies criticism. Reviewing it is like reviewing the world's tallest building. It doesn't care; it just goes on and on."