"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."
-- Adalbert Waffling's 1st Fundamental Law of Magic (WHH)
Adalbert Waffling was a famous magical theoretician and the author of Magical Theory (PS5, DH2, FW). Albus Dumbledore, which whom he corresponded, credits Waffling with the codification of the “Fundamental Laws of Magic” (DH2, WHH, TBB).
"waffle" Brit - to talk on and on without saying much of anything
There is an inconsistency of dates with Waffling. His date of birth is given as 1899 on his Famous Wizard Card. However, in Harry Potter and the Deathly Hallows he is mentioned as a correspondent of Albus Dumbledore's when the latter was a young wizard (DH2). The implication is that Waffling was at that time an older, more important person in wizarding academia. It's possible that Elphias Doge, who wrote the eulogy from which the reference comes, simply misremembered something which happened a century ago. However, if we accept this reference as correct, we must consider the Famous Wizard Card reference to be suspect.
From the Web
The Rowling Library, TRL Magazine Issue #38: Who is Adalbert Waffling?
Harry Potter Wiki: Adalbert Waffling