The Book of Admittance was a large, parchment book bound in black dragon hide at Hogwarts School of Witchcraft and Wizardry, in which the Quill of Acceptance wrote down the birth of every magical child. A powerful magical artefact in its own right, the book served as a regulatory system, refusing to allow the quill to write in it until sufficient evidence of magical ability was displayed, thus guarding against Squibs being incorrectly admitted.