This is a compilation of material from the early part of John Martyn's career on the Island record label (late 60s-early 80s). As such, it's hard to see the point of this album. There have already been two good compilations from this era (the double CD 'Sweet Little Mysteries - The Island Anthology' and the single CD 'An Introduction To John Martyn').
The choice of songs, and the songs themselves, are excellent, and would merit 5 stars. The one distinctive feature of this compilation is that includes a few tracks from the very early 'folky' albums, which other compilations tend to ignore. However, this is a pointless compilation and isn't worth buying. There are better alternatives.
If you are new to John Martyn, the compilation album 'Sweet Little Mysteries' covers the Island period better and the compilation album 'Patterns In The Rain' covers his later career. If you are already a John Martyn fan, there is no new material here and no tracks that you won't already have on the original studio albums. If you want to hear what John Martyn is doing now, buy his excellent new album 'On The Cobbles'.