"The supplemental disc for Led Zeppelin IV is constructed as a mirror image of the finished album, comprised almost entirely of alternate mixes and instrumentals. "The Battle of Evermore" and "Going to California" belong to the latter category, consisting of nothing but the acoustic guitar and mandolin parts from the finished track, while the rest of the record is devoted to alternate mixes from various sources. Occasionally, a distinction leaps out -- there's a notable lack of swampy, cavernous echo on "When the Levee Breaks," perhaps a few more keyboards on the midsection of "Stairway to Heaven" -- but generally these mixes are leaner, tighter, and not all that different from the finished version. A song or two feels slightly different -- "Misty Mountain Hop" jumps a bit as it seems to groove a little bit stronger -- but by and large this disc shows that as a producer, Page not only knew where he wanted to go but he knew how to get it right the first time".