Beginning in the 19th century, readers learned to not write in books. With the development of the public library system and new standards among book collectors, and as it became more common to pass on school texts from one student to another, the habit gradually disappeared. However, reading “quill-in-hand” was common practice for readers at the time of the Ancien Régime. The hundred or so annotated works in the Old Library of the Centre Culturel Irlandais are a testament to this widespread custom. The collection spans the entire period between the 15th and 18th centuries, with a large number of books dating back to the 17th century. These works illustrate the practices of the intellectual elite as they wrestled with treatises on law, history, theology, and religious controversy. While some readers were content to add their signature or a few words to the title page, others filled the margins with personal observations called, in the strictest sense of the word, marginalia.