Parentless Concepts
- Rabbi Ya‘aqov Ashkenazi
- Rader, Matthäus
- Radzin
- Raimondi, Giovanni Battista
- ram
- Ranft, Christoph
- Raniero Sacconi, Opusculum contra Waldenses: Capitula aliqua, primo de causis haeresis
- Rantzau, Heinrich
- Raphael Holinshead, Chronicles, comprising The description and historie of England
- Raphelengii Glossarium latino Arabicum
- Raphelengius, Franciscus
- Rath
- Rath, Hieronymus Arnold
- Rath, Kaspar
- Rattes, Johannes
- Rayd, Hieronymus
- Razi
- Redeius, Franciscus
- Rederer
- Redzenberger
- Refutations of the Qur'an
- Regensburg
- Reginaldus, Nicolaus
- Regino of Prüm
- Regino of Prüm, De synodalibus causis et disciplinis ecclesiasticis