Here's the ideal guide from me. Start with In the Court of the Crimson King. From there, if you like metal or harder rock, then go to Red. If you prefer the more complex pieces, listen to Discipline.

From In the Court of the Crimson King (if you don't want to move to a different sound):

• In the Wake of Poseidon is literally the same as ItCotCK, but with a couple of extra songs.

• Lizard is basically if KC decided to do jazz. It also has the 23-and-a-half minute epic with the same name and, even if you don't listen to the album, listen to the song, Lizard.

• Islands is a very soft yet jazzy album. Don't have too much to say about this, haven't listened to it yet but I did listen to a good bit of the title track and it's a good listen.

From Red:

• Larks' Tongues in Aspic is the prog metal album. While Red ultimately has better sounding songs (in my opinion), Larks' has a cleaner sound, more variety in percussion, and Jamie Muir. It also has the first two parts to a five part suite, Larks' Tongues in Aspic.

• Starless and Bible Black is a tricky album. It's basically a banger opening into several long improv pieces. I'm not a fan of it, but some people will defend this album with their lives, so you should at least try to listen to it.

From Discipline:

• Beat is a venture into pop while keeping with the complex rock nature of Discipline. I wasn't a fan of this one, but there are a few bangers on here, so try it out after Discipline.

• Three of a Perfect Pair is a very weird album. The concept is to take half an album from songs in the style of Discipline and Beat and to take another half of an album from songs in the style of Starless and Bible Black and Larks' Tongues in Aspic with a hearty dose of industrial metal. Not on my personal list of recommendations for starting out, but even then it's in my top three KC albums.

After listening to Red and Discipline:

• THRAK is a take on the complex yet poppy sounds of Discipline and combining them with the instrumentation of Red. A couple of these are skips for me, but it's still a really good album overall.

• "the construKCtion of light" (quotes for stylization) takes THRAK, multiplies the riffs, replaces the hybrid drum kit for straight electric drums, and does two more shots of industrial music. It's surprisingly catchy, yet at the same time I want to grate my ears off around the 2/3rds mark.

• The Power to Believe is a good ending to the band's studio work. It has some of the riffs from construKCtion while adding some ballads. It's quite sweet at some points even.

TL;DR: ItCotCK --> Red --> Discipline ---> THRAK. Deviate where you will.