I have had a number of discussions over the years with people who believe this is the number one record of all time. I can see that for sure. It was so many miles past innovative. Although overplayed throughout the years most of it’s contents (except ‘Money’) haven’t grown old.

By condensing the sonic explorations of Meddle to actual songs and adding a lush, immaculate production to their trippiest instrumental sections, Pink Floyd inadvertently designed their commercial breakthrough with Dark Side of the Moon. The primary revelation of Dark Side of the Moon is what a little focus does for the band. Roger Waters wrote a series of songs about mundane, everyday details which aren't that impressive by themselves, but when given the sonic backdrop of Floyd's slow, atmospheric soundscapes and carefully placed sound effects, they achieve an emotional resonance. But what gives the album true power is the subtly textured music, which evolves from ponderous, neo-psychedelic art rock to jazz fusion and blues-rock before turning back to psychedelia. It's dense with detail, but leisurely paced, creating its own dark, haunting world. Pink Floyd may have better albums than Dark Side of the Moon, but no other record defines them quite as well as this one.

Wiki: The Dark Side of the Moon is the eighth studio album by English rock band Pink Floyd, released on 1 March 1973 by Harvest Records. Primarily developed during live performances, the band premiered an early version of the record several months before recording began. New material was recorded in two sessions in 1972 and 1973 at Abbey Road Studios in London.

The record builds on ideas explored in Pink Floyd's earlier recordings and performances, while omitting the extended instrumentals that characterised their earlier work. A concept album, its themes explore conflict, greed, time, death, and mental illness, the latter partly inspired by the deteriorating health of founding member Syd Barrett, who departed the group in 1968. The group employed multitrack recording, tape loops, and analogue synthesisers. Snippets from interviews with the band's road crew, as well as philosophical quotations, were also used. Engineer Alan Parsons was responsible for many sonic aspects and the recruitment of singer Clare Torry, who appears on "The Great Gig in the Sky". The sleeve, which depicts a prism spectrum, was designed by Storm Thorgerson, following keyboardist Richard Wright's request for a "simple and bold" design, representing the band's lighting and the record's themes. The album was promoted with two singles: "Money" and "Us and Them".

The Dark Side of the Moon received critical acclaim, and is often named one of the greatest albums of all time. The record reached number one on the US Billboard Top LPs & Tape chart (now known as the Billboard 200), and has charted for 950 weeks in total. With estimated sales of over 45 million copies, it is Pink Floyd's best seller, and one of the best-selling albums worldwide. The record helped to propel Pink Floyd to international fame, bringing wealth and recognition to all four of its members. It has been remastered and re-released on several occasions, most recently for digital distribution. Full article