Check If Workbook Is Protected

I just noticed that if you already have a workbook protected and then run code that will protect it, it will become unprotected! (I have a line of code to protect the workbook in the workbook_open event; incase the last user unprotected the book on the last use). Apparently it doesn't work like protected worksheets, where if the sheet is password protected and you have code that tries to reprotect it with a different password nothing will happen. I can not find a way to check if the workbook is protected (and if so skip, but if not then protect). Worksheets have "activesheet.protectcontents" to tell you True/False.