<p>A <b>book</b> is a set of written, printed, illustrated, or blank sheets, made of <a title="Ink" href="https://en.wikipedia.org/wiki/Ink">ink</a>, <a title="Paper" href="https://en.wikipedia.org/wiki/Paper">paper</a>, <a title="Parchment" href="https://en.wikipedia.org/wiki/Parchment">parchment</a>, or other materials, fastened together to hinge at one side. A single sheet within a book is a <a class="mw-redirect" title="Recto" href="https://en.wikipedia.org/wiki/Recto">leaf</a>, and each side of a leaf is a <a title="Page (paper)" href="https://en.wikipedia.org/wiki/Page_%28paper%29">page</a>.</p>