Quote from : Guards! Guards! Book

The Librarian swung on. It was slow progress, because there were things he wasn't keen on meeting. Creatures evolved to fill every niche in the environment, and some of those in the dusty immensity of L-space were best avoided. They were much more unusual than ordinary unusual creatures. Usually he could forewarn himself by keeping a careful eye on the kickstool crabs that grazed harmlessly on the dust. When they were spooked, it was time to hide. Several times he had to flatten himself against the shelves as a thesaurus thundered by. He waited patiently as a herd of Critters crawled past, grazing on the contents of the choicer books and leaving behind them piles of small literary criticism. And there were other things, things which he hurried away from and tried not to look hard at... And you had to avoid cliches at all costs.