Right now, when sorting the Books/Videos page by Most Recent and “Collapse series” is set to “yes”, items within a series are still shown from least recent to most recent. A long while ago this actually did short from most recent to least recent, but this broke when @brandon did a rewrite of this page. However, I figured it’s probably a good time to ask for this to be fixed. 
Additionally, there’s the question of what the “started” column should show in the series row. Right now it shows the exact start and end values of the least recently read volume. Naively, after the fix this would show the exact start and end values of the most recently read volume instead. However, I’d suggest considering showing the full date range of the series, meaning the start date should be the earliest date and the end date should be the latest date. (Note: A start date isn’t always specified, so I’d use the earliest date of any start or end date as the start date for the series.)
