Strange Hobby is an uncredited cover album by Arjen Anthony Lucassen, released in 1996.
 The album and the booklet contain no information about Lucassen and don't explain who was responsible for the recordings, to make the album even more "strange".
Pools of Sorrow, Waves of Joy is the debut solo album of Dutch composer, singer, and multi-instrumentalist Arjen Anthony Lucassen, released under the name Anthony.
 He sang leading vocals and played most of the instruments himself.
 However unlike most of his future works Lucassen doesn't play bass, with Peter Vink (future member of Lucassen's band Star One and future contributor of Lucassen's project Ayreon) playing all bass.
Live on Earth is the first live CD and DVD by Arjen Anthony Lucassen progressive metal project/supergroup Star One.
 It features songs from their debut album "Space Metal", but also numerous songs from Lucassen's other project Ayreon.
Ayreon is a musical project by Dutch songwriter, singer, multi-instrumentalist musician and record producer Arjen Anthony Lucassen.
 Ayreon's music is described as progressive rock, progressive metal and power metal sometimes combined with genres such as folk, electronica, experimental and classical music.
 The majority of Ayreon's albums are dubbed "rock operas" (or "metal operas") because the albums contain complex storylines featuring a host of characters, usually with each one being represented by a unique vocalist.
The Human Equation is the sixth album from the progressive rock project Ayreon by Dutch musician Arjen Anthony Lucassen, released on 25 May 2004 via InsideOut Music.
 As with other Ayreon albums, it features guest appearances from several musicians previously unrelated to the project, including James LaBrie of Dream Theater, Mikael Åkerfeldt of Opeth, Eric Clayton of Saviour Machine, and Devin Townsend, performing music arranged and written by Lucassen.
A rock opera is a collection of rock music songs with lyrics that relate to a common story.
 Rock operas are typically released as concept albums and are not scripted for acting, which distinguishes them from operas, although several have been adapted as rock musicals.
 The use of various character roles within the song lyrics is a common storytelling device.
 The success of the rock opera genre has inspired similar works in other musical styles, such as rap opera.
 These albums are also referred to as "concept albums".
Star One (also referred to as Arjen Anthony Lucassen's Star One) is a Dutch progressive metal supergroup/side-project of Arjen Anthony Lucassen of Ayreon fame.
The Theater Equation is a live album and DVD/Blu-ray by Arjen Anthony Lucassen's progressive rock/metal rock opera project Ayreon.
 "The Theater Equation" originally consisted of a four live performances, with cast, choir and small orchestra, of the 2004 album "The Human Equation", as an actual rock opera, complete with mise-en-scène.
 It is the first Ayreon live release, although Ayreon songs had previously been featured on live albums by two of Lucassen's other musical projects ("Live on Earth" by Star One and "Live in the Real World" by Stream of Passion), and marks the first time an Ayreon album was performed live in its entirely.
 "The Theater Equation" consisted of four shows, all played in Rotterdam between September 18 and 20, 2015, with the last performance being the one recorded for the album.
On This Perfect Day is the debut album by Arjen Anthony Lucassen's side project Guilt Machine, released in August 2009.
 The cover of the album was made by Christophe Dessaigne, an artist discovered by Arjen Lucassen on Flickr.
Lost in the New Real (also referred to as Arjen Anthony Lucassen's Lost in the New Real) is the second solo studio album by Dutch songwriter, producer, singer, and multi-instrumentalist Arjen Anthony Lucassen.
 It is Lucassen's first solo album since "Pools of Sorrow, Waves of Joy" released 18 years ago under the name Anthony, before he reached fame with his progressive metal/rock opera project Ayreon.
 He sang lead vocals for the first time since the first album, and played most of the instruments himself including all guitars, bass and keyboards.

Question: What kind of albums has Arjen Anthony Lucassen produced that would be considered "concept albums"?
Answer: Rock operas