A Swedish Death/Doom/Gothic Metal band. Their name is a pretty good description of their music. On the first three albums they utilized minimalistic guitar chords and drum patterns, combined with extremely powerful growling vocals to create unique and melancholic music. On their more recent releases, they have begun using clean vocals and more complex song structures, which surprisingly produces much of the same spirit than the earlier aggressive material.
The creative energy behind the music are the lead singer Jonas Renkse and guitarist Anders Nyström (who went by the pseudonym 'Blackheim' on the earlier albums). In the tradition of the best swedish masterminds of metal, they have not limited themselves to just Katatonia, but both of them have side projects as well. Renkse has put out two albums with a project band called October Rain, which is very similar to the earlier works by Katatonia. Nyström has released numerous albums by the name Diabolical Masquerade, which is more in the Black Metal vein.
Here's a list of releases by Katatonia with a bit of IMHO's on the side:
Jhva Elohim Meth.. the Revival
1992
On this album (which I haven't heard much due to the fact that it's extremely hard to find) Katatonia still went by the traditional Black Metal imagery, which the music didn't quite match. The basic foundation of the music was already there though.
Dance of December Souls
1993
Pretty much like the first release, only with more feeling and longer songs.
For Funerals to Come EP
1994
A mixture of the styles of the previous album, and the one that would follow...
Brave Murder Day
1996
Their finest hour. Uses very simple guitar structures, and the vastly powerful guest vocals of Mikael Åkerfeldt (borrowed from Opeth) to create the only peace of music I have ever heard, which manages to create such melancholic atmosphere without being ridiculously slow at the same time. A true classic.
Sounds of Decay EP
1997
Features three song in the same vein as Brave Murder Day, but doesn't quite manage to capture the mood of it's precursor.
Saw You Drown EP
1998
Another hard to find. This was their first experiment, which would eventually evolve into what Katatonia is today with clean vocals and Nyström's superb guitar work.
Discouraged Ones, 1998
Tonight's Decision, 1999
Teargas EP, 2001
Last Fair Deal Gone Down, 2001
Tonight's Music, 2001
I grouped these releases together, because musically they are pretty much the same, with only some advances towards cleaner production on the later albums. Despite the fact that the music is nowadays much cleaner and, dare I say, radio friendly, the basic idea is still there. Melancholy.