The late Carl Sagan was one of those rare scientists who could communicate some of the pleasures of science to the general public: the passion for learning, the deep satisfaction of discovery, and majesty and awe of the Universe in scales both large and small. His documentary Cosmos stands as one of the best in television history, and now it is available on an excellent DVD set.

One of the pleasures of Cosmos is that Sagan doesn't overload the viewer with detail: this is very much a "big picture" documentary. Some of the conventions strike the modern viewer as somewhat corny. For example, the "spaceship of the imagination" that Sagan uses to flit about the Cosmos looks like a bad Star Trek set, and some of the metaphors (like using a scooter to explain the speed of light) don't really work all that well. But generally, the use of historical re-enactments and on-location commentary by Sagan helps to contextualize the various issues very well.

In spite of that, Cosmos is still a benchmark for the science documentary, and it holds up extremely well over twenty years after it was first aired. Carl Sagan recorded some updates prior to his death in 1997, and these updates are included at the end of the episodes. It is a testament to the filmmakers that the updates are clarifications rather than reversals: Cosmos is still an excellent reference.

The thing that sets Cosmos apart from other documentaries is that it places scientific discoveries in context. Kepler's discoveries of planetary motion are discussed, but they are presented in historical context of his life, with the religious and societal implications. Cosmos was the first popular science program to give Kepler his due, rather than focusing exclusively on Newton and Galileo.

Sagan also spends time debunking pseudo-science like Astrology and alien abduction, but he does it gently and with good humor. Sagan was often criticised by the scientific establishment for "talking down" to people, and oversimplifying scientific concepts, but what comes through is Sagan's essential humanity. He was genuinely concerned for the human race, and one of the themes of Cosmos was the nuclear confrontation between the United States and the Soviet Union. This is a rather jarring note for the modern viewer, but the looming specter of nuclear war preyed on Sagan's mind. In one of the updates he expresses relief that the confrontation between the superpowers had ended with the collapse of the Soviet Union.

It's astonishing that over two decades after it was initially aired, Cosmos still stands as one of the best documentaries ever made.

The DVD transfer is pristine and handsomely packaged. The video has been extensively cleaned, and the audio is crisp and well-balanced. There aren't many extras apart from the updates appended to some episodes, but this isn't really a fault: Cosmos stands well on its own.