How do I know if a title is currently lent or available ?

If you need to know whether a title is on the shelf or borrowed, simply hover its book cover picture in the Titles main window: a help tip pops up and tells you if the title is available or not

Alternative: just double-click on this title in the Titles file. You get all the references about this title : author, publisher, shelf mark etc. By clicking on the Copies tab, you get the number of copies and their status (lent/on shelf).