In Life* there are many hundreds of common experiences, feelings, situations and even objects which we all know and recognize, but for which no words exist.

On the other hand, the world is littered with thousands of spare words which spend their time doing nothing but loafing about on signposts pointing at places.

Douglas Adams and John Lloyd saw it as their job to get these words down off the signposts and into the mouths of babes and sucklings and so on, where they could start earning their keep in everyday conversation and make a more positive contribution to society.
"The Meaning of Liff" was the bestselling humour book that resulted.
It sold hundreds of thousands of copies and remains to this day, nearly thirty years later, a much-loved classic of its kind.

*And, indeed, Liff.