The Book Didn’t Change—You Did

Why re-reading books (and re-learning concepts) makes you better.

There’s a quote from the ancient Greek philosopher Heraclitus that says:

"No man ever steps in the same river twice, for it’s not the same river and he’s not the same man."

At first, it sounds like a riddle. But it’s actually one of the deepest truths about learning.

I’ve re-read books that I’ve read before—sometimes two, three, even four times.

And every t…