Stop, Exposition Time?

Fairly recently, I read a chapter in a book (not going to name it here) that quite literally consisted entirely of exposition delivered by a character in direct speech; it was not very short either, but rather trailed on an on page after page. Although it made sense for the character to be doing this, the whole thing felt dull and artificial, interrupting the action (which, up to that point, had been building up to something a lot more exciting) in favour of a monologue. But how does one handle such a situation properly anyway? Is there even a way to do that? Opinions likely differ, as on all story-telling devices, and I won't consider myself an "expert" on them, but here's what I feel is some decent advice about exposition.

As the old writing advice goes, "show, don't tell". Evidently, the most obvious way to handle exposition well is to not have it. If there is any way to demonstrate the information through events and "natural" dialogue instead of just blatantly spelling it out, then that usually works a whole lot better, as it does not interrupt the flow and leaves something for the reader to figure out and "work" to comprehend as a whole. "Time skips" to the past can be useful for this if the important event happened prior to the story's present, but care must be taken not to confuse the reader (unless you are deliberately trying to do so, which is rarely a good idea unless there's a very good reason for it); containing the past sequence within its own chapter may help, as it clearly separates it as a self-contained instance

Sometimes, however, there's just no practical way to show all the information that the reader requires. What is to be done when something absolutely needs to be delivered by a character? The most important thing to remember here is that such a segment is not you (the author) explaining things to the reader. What you have on your hands is a character who is talking in-story, likely to other characters. Let them talk as the character they are and let others react to what they are saying where applicable. Make sure lengthy exposition does not interrupt the flow of the story. No monologue is important enough to stop time, and if something else should be going on during it, make sure it does go on! Having the exposition interrupt an interesting scene completely is a surefire way of making the reader wish it were finally over or, in the worst cases, just skim through it in order to return to the action.

In monologues, do not forget to take advantage of the speaker's personality (if possible) to make what they are saying entertaining to read. Some people are good at semi-improvised story-telling; perhaps your character can wrap the information in an exciting tale in its own right (if they cannot do it by themselves, maybe they can read from a book-within-your-book that does a better job at dramatising the events in question), perhaps they can spice it up with their own remarks and humour. Whatever they do to make the explanations more bearable, make sure it fits the character and "sounds" like something that would realistically come out of their mouth. Never talk through your character as if you were mind-controlling them.

All in all, exposition is a tricky thing to do. However you decide to handle it, don't forget its primary purpose of helping the reader understand your story better; do not let boatloads of background knowledge overtake said story.