Timeless good, unique, top notch rock album, cornerstone of rock music ... etc! All true, but only scratches the surface - it was in 1972 as this album was in the record stores and today it is so fashionable and trend-setting as it was then! Whether you are (like me) the opener "Black dog" Preference or the absolute high-flyer "Stairway to Heaven" was chosen as the personal favorite of the album .... the other songs are not bad !!! Consistently horny rock music from hard to soft ("Going to California"), each title is an "ear candy" !!! The disc has only one big mistake - at some point the last track is over! LZ IV - the masterpiece of 4 hard rockers - belongs in any collection !!