The Hitchhiker's Guide to the Galaxy is a science fiction comedy series created by English writer, dramatist and musician Douglas Adams. Originally a radio comedy broadcast on BBC Radio 4 in 1978, it was later adapted to other formats, and over several years it gradually became an international multi-media phenomenon.

It is the source of multiple activities and traditions in CTYI. The main tradition, 'Dressing Gown Thursday', is based on the story-line in the book.

Also See

42 - Answer to the Ultimate Question of Life, the Universe, and Everything.

Traditions - All regular CTYI traditions.