Lewis Carroll’s 1885 puzzle book A Tangled Tale bears an anonymous dedication:

Beloved Pupil! Tamed by thee,
Addish-, Subtrac-, Multiplica-tion,
Division, Fractions, Rule of Three,
Attest thy deft manipulation!
Then onward! Let the voice of Fame
From Age to Age repeat thy story,
Till thou has won thyself a name
Exceeding even Euclid's glory!

He was thinking of Edith Rix, a child-friend who went on to study mathematics at Cambridge. She might have divined without asking that the dedication was intended for her. How?