I'm surprised nobody mentioned https://www.libib.com/. It comes with a mobile app that has a barcode scanner with an option for manual entry.
Yes, some older books, especially in languages other than English, are not in its database, leaving you with the manual option, but it will let you index the books that are there in no time.
At the moment I can't see how old are the items – I really miss dates.
Also, pagination with Next/Prev buttons is ambiguous. Replacing the labels with Older/Newer would make it clear, in which direction in the timeline I'm moving.
I very much like the summaries. It would be great if they had unique URLs. This way I could share the URL of the story summary.
Yes, some older books, especially in languages other than English, are not in its database, leaving you with the manual option, but it will let you index the books that are there in no time.