Bruji

If I select multiple books in cover view, either using command or shift click, then I right click on one of the selected books to perform an action, such as "edit book" or "Mark as..." all but the single book I right clicked on are deselcted.

This function works properly in Table View.

Thank you, that is a limitation/bug we are aware of; ctrl-click selects the entry clicked in cover view and we haven't been able to get around that. Use the menu command or the shortcut (command-e) to start the multi-edit in cover view.

What about the "mark as read" option, is the best bethod to do a command-e and manually enter the date?

All the commands in the contextual menu are also part of the regular top menu. You will find "mark as" under the edit menu, as well as the keyboard shortcuts for each; you don't even have to reach for the mouse.