[electronvolt]

I've had an algebra professor who lectured by preparing notes for the class and then reading them and writing them on the board verbatim. After particularly difficult proofs he'd sometimes turn around to look at the class, to see if anyone had their hand up, before moving on.

Said professor has made serious contributions to modern algebra and is probably about as close to "the forefront of modern mathematics" as anyone. Not everyone who's good at math is good at lecturing.