I opened an existing InDesign document, where yesterday the paraghraph styles were still there.
Today the paragraph styles field is empty! I can't load them from another document. Restart did not help.
Character Styles are not involved.
1 of 2 things - your document is corrupted or you have inadvertenlty removed them.
Do you have a backup of the file?
For corrupted files try this http://forums.adobe.com/thread/526991
Blank panels is usually corrupt preferences. See Replace Your Preferences
It works! Thanks so much! I trashed the preferences by Ctrl + Alt + Shift.
Retrieving data ...