Though fully scripted and recorded as a four-parter, parts three and four were merged into a single episode, effectively leaving an episode on the cutting room floor. This edited material was not retained — though some of it made it into the novelisation. In a sense, then, Planet of Giants was the first serial to have a missing episode. Aside from being Marks' first work on the series, it was also the Doctor Who debut of long-time composer, Dudley Simpson, and the first credit for frequent director Douglas Camfield.