What a notebook remembers

A notebook keeps its earlier versions. History, in the notebook menu, lists them, previews the one you select read-only, and offers a single Restore. The preview renders the version as a page rather than as its source, so you are choosing between two documents you can actually read.

Restore does not ask you to confirm, on purpose. Restoring snapshots the notebook as it stands before it replaces it, so the state you just left becomes a version of its own and restoring again takes you back to it. There is no one-way door here, which is what makes trying a restore a reasonable thing to do.

Lock editing stops accidental edits, on this device and on others. It is a guard against a stray keystroke in a notebook you consider finished, and it is not sharing: locking changes nothing about who can see the page.

Deleting a notebook is recoverable. Delete notebook removes the notebook and its cells, while items and highlights you kept stay in your Library; the notebook itself goes to trash and can be restored for 30 days. A cell elsewhere that referenced it does not break in the meantime: it renders as a tombstone saying what used to be there, with a door that brings the notebook back.