I haven't used Lightroom for awhile and I'm trying to finish a phonebook I started. I finally figured out that the list of modules that is usually along the top right is missing on my screen (Library, Develop, Map, Book, etc.). The only way I can select a different module is to go to 'Window' and scroll down to the module I want there. How can I get these to show up again? It's just black space where they're supposed to be.
Please note the small triangle on top middle, actually on all sides. Click on it and right-click on it to see the options.
Also try what happens when you hit Shift+Tab or Tab - very useful shortcuts.
Also in addition to above answer- If you have any module visible on the top row, you can right-click on a module name and tick/check to select which of the module names you want to show (or hide).
Example: If you never use Maps you can uncheck "Maps" and hide it on the module menu strip.