Doctor Who is the world’s longest-running sci-fi series. As the show has stacked up over 800 stories in its 60 years, it’s also built an impressive legacy of home media. The classic Fourth Doctor story Revenge of the Cybermen was the first adventure to make it into fans' homes. But in 1983, it was a major investment to own a single Doctor Who story on Betamax, Video 2000, or VHS. Jump forward 40 years, and the BBC’s flagship genre show has embraced high definition and box sets.