In Absentia

In the band's earlier years, while under Delerium Records, the band's music typically possessed more extended and abstract qualities typically associated to psychedelic rock and space rock.[5][6] The band shifted their sound in the late 1990s when signing to Kscope/Snapper Record labels, to a more commercial, radio friendly sound that entailed shorter compositions and traditional song structures, while retaining progressive rock qualities as well.[6][7][8] However, by around 2001, they had again outgrown a smaller record label, and after changing labels again to Lava Records, decided to move in a more progressive metal direction.[9] The band had originally been opposed to major record labels, believing that most labels didn't "get" the band, and their emphasis on albums over singles approach in this era of music.[10] However, they chose Lava because they appeared to support this philosophy, Wilson attributing this due to other bands, namely Tool and Radiohead, achieving success with the same mindset.[10]

A number of other factors affected the change in sound beyond the change in record label. Many were key personnel changes and relationships. Most prominently was frontman Steven Wilson's rediscovering of heavy metal music through his fascination with Burzum and the book Lords of Chaos, which led him to listen to many extreme metal bands and finally the Swedish acts Meshuggah and Opeth whom he described as "the holy grail" of this new scene (both groups were thanked on In Absentia's sleeve notes).[11] Furthermore, Wilson would end up meeting Mikael Åkerfeldt from Opeth, which occurred when the two were separately interviewed by an interviewer who had interviewed both of them.[12] Impressed with their music, Wilson eventually agreed to produce the next Opeth album, Blackwater Park,[13] which inspired Wilson to move Porcupine Tree in a more metal direction as well.

Another factor in the change of the band's sound was due to Wilson's meeting of Israeli rock singer Aviv Geffen. The two met when Geffen, a fan of Wilson's music, invited Porcupine Tree on a tour in 2000 in support of the band's previous album, Lightbulb Sun.[14] Touring together lead to a separate musical collaboration named Blackfield. Geffen, not being a fan of metal music, kept that project in more of a pop rock genre, sounding more like prior Porcupine Tree albums Stupid Dream and Lightbulb Sun.[15][16] This gave Wilson an outlet for that side of his music, allowing him to concentrate on more metal sounds with Porcupine Tree without abandoning the prior genre altogether either.[15] Rounding out the changes was the departure of drummer Chris Maitland, with the replacement being Gavin Harrison, who joined in early 2002. Maitland was unable to make a larger commitment with being signed to a major record label, and the band found Harrison's style more fitting to a more metal-sounding album.[17][18] Wilson summarized the band's changes at the time as:

In Absentia was all written before Gavin came on; even the drum parts were kind of programmed. But it’s one of those times sometimes in life when everything comes together. I’d written these songs and I was very much more interested at that time—having worked with Opeth—in the idea of combining a more kind of brutal or metal aspect back again into the fabric of the music. At the same time Gavin came along and Gavin was a very different drummer to our previous drummer, Chris Maitland. He was much more of a powerhouse and he was much more technical. He had more of a contemporary edge to his sound so it was just one of those really lucky things that he just came in and he played those songs and just blew everyone away and everything just kind of came together. And of course it was the first record we made for our new label and we got signed to a big American label for the first time [Lava Records]. Gavin was the final piece of that equation in a way—he just totally raised the bar in terms of not just the drumming but just the musicianship right throughout the band. Everyone was listening to Gavin and saying, “Fuck, wow. We really need to step up our game.”[6]

After the recording process was complete, Steven Wilson then took the album to Larrabee Studios in Los Angeles to work with Tim Palmer and his engineer Mark O'donoughue mixing the record on the J-Series SSL console.

While not a formal concept album, many of the songs still have common themes related to serial killers, youthful innocence gone wrong, and criticisms of the modern world.[19] The album's title is also tied into this, with the phrase being Latin for "in absence"[20] or "in one's absence", often in reference to a person's rights when mentally unable to be represented in court in legal situations.[21] Wilson said of the title:

"It comes from... It's related to some of the lyrics. It's about people on the fringes, on the edges of humanity and society. I have an interest in serial killers, child molesters, and wife beaters... Not in what they did, but in the psychology of why. What caused them to become unhinged and twisted? Why are they unable to empathise? It's [In Absentia] sort of a metaphor - there's something missing, a black hole, a cancer in their soul. It's an absence in the soul."[22]