Professional ratings
Review scores
Source	Rating
Classic Rock
Dangerdog Music Reviews
Metal.de
Metal Hammer (GER)
Metal Injection
Metal Mouth
Myglobalmind
Nightfall in Metal Earth
Sputnikmusic
Ultimate Guitar Archive	8.6/10

The Theory of Everything (stylized as ŦĦΣ ŦĦΣΦɌ¥ ΦƑ ΣVΣɌΨŦĦIΠG) is the eighth studio album from Ayreon, a progressive metal/rock opera project by Dutch musician Arjen Anthony Lucassen, released on October 28, 2013.

As with every Ayreon album, it is a concept album with each character being portrayed by one singer, however being released five years after 01011001 which concluded the original Ayreon story, The Theory of Everything is a fresh start from the Ayreon storyline developed since Ayreon's first album The Final Experiment in 1995; in addition, while previous albums which took place in a sci-fi context (with the notable exception of The Human Equation, taking place in a man's mind), it is set in a realistic world. Lucassen composed all the music, and wrote the story and lyrics with his girlfriend Lori Linstruth, making it the first Ayreon album in which he shares lyrics credit for all the songs.

In the typical style of the project, the album features several guest singers to portray the characters across the album, including former King Crimson and current Asia member John Wetton, Marco Hietala of Nightwish and Tarot, Cristina Scabbia of Lacuna Coil and Tommy Karevik of Kamelot and Seventh Wonder. It also features various guest musicians such as keyboardists Rick Wakeman (ex-Yes), Keith Emerson (ex-Emerson, Lake & Palmer), and Jordan Rudess from Dream Theater, and guitarist Steve Hackett (ex-Genesis). It is Lucassen's first collaboration with every singer on the album, with the exception of backing vocalist Wilmer Waarbroek, who already sung on his solo album Lost in the New Real.

...
Wikipedia