Super-simple and does what it promises

After initial issues (this did not work when you weren’t using standard WordPress login pages), and excellent support from the developer, this now does what it promises to do – in a way as elegant and simple that it is without competition.
A simple checkbox on the post – and the post is hidden to users who aren’t logged in.
People with a direct link to the post now can get a login popup – and if they have a user ID and password, they can see the post.

Exactly what I needed.