When you’re writing a complex tale – say a mystery, or a tale of vast government conspiracy – it’s important to remember that readers may not be sitting down and devouring your work in a single setting. They may be gobbling up chapter-size bites on public transit or between chores. If your novel is long, it’s best to remember that no one can really keep it all straight in the skull for too long. That’s where summary scenes come in.
We all recognize them: the scenes that play out like the “Previously on Lost” recaps on TV. Two or more characters have a chat about what’s been going on. A character is making notes about what they’ve learned. A cop interrogates a witness through several recent crimes’ worth of material. If done right, they feel natural and are a breather. If done wrong…. well, they suck. Let’s not bother to beat around the proverbial bush.
Roz Morris has a great post on this topic that I recommend writers take a peek at. She discusses when to use these scenes and how to ensure they’re done well. Take a look!
A.C. Dillon 
Thanks for the mention! The ‘previously’ scene is an interesting analogy – series have it easy as they just front-end all the info we need for that week’s episode and present it in flashbacks. People writing a story that’s not going to be split have a far more difficult job – but readers still appreciate the recap.