Douglas Adams- How did he get published?

Did Douglas Adams have a hard time publishing his books, or did things go pretty smoothly?  It just seems strange to read a book with his writing style, because normally editors would dencounce it as amatuer at first glance.  Like internet fanfics, there's plenty of silliness and asides that wouldn't get through an editor who has to skim through unprofessional writing to find a "professional, by the book" book.  His style seems very non-standard, when editors typically look for normal written manuscripts that meet strict criteria.  Did he just have a generous editor or agent he was friends with, or did he have trouble getting it published?

If only he knew he was going to die.  Then he could finish The Salmon of Doubt.