For over 500 years, paper was only available and sold as single sheets. In 1902, an inventive Australian used half size sheets of paper, a bit of glue and cardboard to create the what?

Birchall's of Launceston in Tasmania started selling the world’s first notepads, calling them 'Silvercity Writing Tablets' after J A Birchall thought it would be a good idea to back sheets of paper with cardboard and glue them together at the top. His British paper suppliers weren’t so keen, but, they were persuaded by Birchall that it was a good idea!