A genius. Very few people can write like he could.
__________________ "Men curse the Communist Party, but eventually it may release them. If hell were endless, then God would be worse than our Secret Police."--Pastor Valentin
Think of Terry Pratchett writing science fiction in the early eighties and you're nearly there... only Douglas Adams could get away with the following ... "The Vogon ships hung in the upper atmosphere in exactly the same way bricks don't..." (Hitchhiker's Guide to the Galaxy novel...) and "FX: Swirling mist, vague shapes fluttering about, and strange flashing lights... all this is signaled by a cough from Arthur, who is played by an amazingly talented actor..." HHGttG Radio Script...
I think Dougie Adams was uniquely talented, almost mad you might say. His concepts were hilariously funny and bizzarly brilliant all at the same time!
For example his idea of learning how to fly - You fall but at the moment just before impacting with the ground you miss. Because you have fallen and missed the ground you are technically flying! The real trick however, is learning to master how to fall upwards and sidewards in order to gain directional control...