This has long been one of my favourite Zeppelin albums. It's more original, the rock songs are peerless, 'Friends' is amazing and one of the band's highlights, and there isn't the same reliance on standard blues workouts. Instead you get a lot more influence from earlier periods - Leadbelly, Blind Willie Johnson, Kokomo Arnold, and Delta slide masters. Bonham is amazing on 'Out on the Tiles', and the guitar work from 'Gallows Pole' to the end is exceptional for its range and colour. Great music!