SAAR Library keeps the catalogue, the members and the circulation desk in one place. Every issue records who took a copy and when it is due, so the overdue list is a query rather than somebody’s memory.

Title, author, an accession code, ISBN, publisher, year, shelf, a cover image and the number of copies you hold — grouped into categories you define yourself.
Each member gets a membership number, a group, a borrowing limit and a membership expiry, so the desk knows at a glance whether somebody may take another book.
Issuing a copy sets its due date and records who handed it over; returning it records who took it back. An issue made in error can be cancelled rather than faked into a return.
A loan past its due date carries that status, so the overdue list and the stock view — copies held against copies out — are always current.
Add categories, then titles with their copy counts and shelf locations.
Give each member a number, a group, a borrowing limit and an expiry date.
Pick the title and the member; the due date is set and the copy comes off the shelf count.
Record the return, or chase what the overdue list is showing you.
No. Each member carries their own borrowing limit, set when they are registered and changeable later.
The stock view compares the copies you hold against the copies currently on loan, title by title.
Cancel the issue. It is recorded as cancelled rather than dressed up as a return, so the history stays honest.
Not today. Overdue loans are tracked and listed; fine calculation is not part of the product.
Catalogue, members, issue, return and an overdue list that keeps itself.