For our younger readers (if there are any? please, speak up!): Once upon a time, there were buildings, called libraries, in which the humans collected their knowledge and tales. Printed on paper and bound in stacks and called books. And one had to turn the page by hand to read on; no page-up- or page-down-buttons were attached. Just so you young ones know what we are talking about here…
Please, define ‘young’?