Frank Cornelius, born Ruud Houweling on June 24, 1978, is a Dutch guitarist, singer, and songwriter, best known for his long and prolific collaboration with Arjen Anthony Lucassen. His career is inextricably linked to the progressive rock project Ayreon, for which he became the lead guitarist, contributing his melodic and technically refined style to critically acclaimed albums such as *The Human Equation*, *01011001*, and *The Source*. In addition to his role in Ayreon, Cornelius is the creative mind behind his personal project, For All We Know, where he serves as the singer, guitarist, and primary songwriter. With this band, he has released the albums *For All We Know* (2011) and *Take Me Home* (2017), works that blend progressive rock with alternative sounds. His versatility has also led him to collaborate with other artists in the scene, including Stream of Passion and The Gentle Storm, solidifying his reputation as an influential and respected musician in the European progressive landscape.