Timothy Chow, in his article *A beginner's guide to forcing*, defines an **open exposition problem** as a certain concept or topic in mathematics that has yet to be explained "in a way that renders it totally perspicuous."

What are some open exposition problems in your field, particularly ones that you think would help interested mathematicians break into it?

For instance, there is no shortage of references on chromatic homotopy theory -- Ravenel's Green and Orange books, Lurie's course notes, and Hopkins' COCTALOS notes. Nonetheless, there does not seem to be a complete, smooth, and carefully-put-together exposition of the chromatic story that assumes neither too much homotopy theory nor algebraic geometry.