In medium saucepan, combine sugar, milk, butter and cocoa. Bring to a boil, and boil for 1 ½ minutes.
Remove from heat, and stir in peanut butter, vanilla and oats.
Drop by teaspoonfuls onto wax paper. Let cool until hardened. *HINT* Start timing when the mixture reaches a full rolling boil. If you boil too long the cookies will be dry and crumbly; if you don’t boil long enough, the cookies won’t form properly.