I use notebooks to categorize notes of a specific topic. A good example is my Car Maintenance notebook or Medical Documents notebook. Each time I get a new invoice for some maintenance done, I scan it with Scannable and stick it into the Car Maintenance notebook. Over the years, that notebook has become quite large, and it becomes difficult to look through it using the view provided by Evernote. I use what I call an "Index" note, which is essentially a table of contents note but with categories. This allows me to a/ easily categorize the notes in a notebook using bullet point lists for each note link, and b/ easily reference that notebook's contents by placing all Index notes in the Shortcuts section. This allows me to use Evernote much like someone would a reference book or cheat-sheet. Except it's a cheat-sheet to everything in your life. There are a couple problems that would be great to have solved: 1) Index notes have to be manually maintained. It would be great if Table of Contents notes were "smart", and auto-updated to include new notes. 2) Index notes allow me to categorize as I see fit, but Table of Contents notes have no categorization, which means that any large notebook's ToC turns into a useless spaghetti list of hundreds of notes. Specifying categories in a ToC would be cool, with a category for "Uncategorized" notes that are new to the notebook but haven't been categorized by the user. 3) Index notes allow for multi-notebook table of contents. I could have in theory an index note that mapped to a stack of notebooks - i.e. if I had a Car stack, with Car Maintenance and Car Accidents as sub notebooks, a fantastic table of contents could exist that mapped both sub notebooks, giving me a really great overview of everything Car related. A lot of this could be solved by doing away with the idea of a user-created Table of Contents and instead having a "Notebook overview" note, or a Table of Contents note that HAD to exist. This note would get auto populated with smart note links to it's constituent notes, as well as any sub-notes, and include a special categorization interface. This is really specific to the way I use Evernote, and I know everyone uses it differently, so it'd be great if people chimed in if they felt something in this vein was useful.