The idea of the Daleks was created by Terry Nation. They appeared in the second Doctor Who story called ‘The Dead Planet‘ in 1963. Ray Cusick designed the original Daleks, since then little has changed to the basic design.
The Daleks come from the planet Skaro some time in the future, their main leader and creator is Davros. Over the years there have been many different Dalek space ships, but the classic design is in the shape of a saucer.
The Daleks have tried just about everything to take over the universe but luckily the Doctor has always stopped them. Vists the Dalek episode guide for more information.