III has always been among my Zep favorites but in the '70s it was over-shadowed by their other albums. I think over time it's become recognized for the great album it is. Branching out into acoustic territory, after the electric onslaught of the first two albums, expanded their reach, a trend they continued through the albums that followed. The first two albums had their quieter moments but the folk slant on side two of III is way more pronounced. Joined with the electric goodies on side one, helluva mix. Everything on the album works, although Hats Off to Roy Harper would be more effective without those irritating phasing effects on Plant's vocals.