This is King Crimson's second album. Others reviewers are correct in that some parts of this album sound too much like the first album. Especially unoriginal is Pictures of A City. Note that before it was put on this album, it was played live as A Man, A City.
But, this album is redeemed by some very good jazzy, instrumentals. A lot of the music more mellow than anything King Crimson would ever do. But it is still very innovative and invigorating.
Note that the track Cat Food is not listed here, but I am sure that it is still on the CD.
King Crimson recorded one album (In the Court of the Crimson King), went on tour, and nearly fell apart. Ian MacDonald, who was a co-leader of the group left. So did Gred Lake, but he was brought back for this album to do vocal. The Giles brothers were still with the band.
After this, Giles and MacDonald recorded an album called MacDonald and Giles. It is better than In the Wake of Posieden and worth seeking out. MacDonald went on to Foreigner, playing corporate rock and making tons of money.
MacDonald, the Giles, and a number of other old King Crimson members have recently got together to form a band called 21st Century Schizoid Band. They have a couple of CD's out, with old King Crimson songs.