Adalbert Waffling (1899–1981) is the author of Magical Theory (PS5). He was a famous magical theoretician whose writings have been learned by every modern witch and wizard (FW). He corresponded with Albus Dumbledore when the latter was a young man (DH2).
Waffling is famous for positing his Fundamental Laws of Magic, the first of which is "Tamper with the deepest mysteries—the source of life, the essence of self—only if prepared for consequences of the most extreme and dangerous kind" (BB3).
Albus Dumbledore's birth date (1881) is incompatible with that of Adabert Waffling. In chapter two of Harry Potter and the Deathly Hallows, it says that during Dumbledore's school years, Waffling was already an acclaimed magical theoretician. According to his birth year, he was not even born then.