Go to http://www.dastelefonbuch.de/. To get the information in English, go to the uppermost grey toolbar on the site and click the link "Sprachen" (languages) on the right. This will open a pop-up menu. Click "English." On the top of the site you will find a menu "Who/What" and "Where."
Put the name into the "Who/What" box and the city, town or village in the "Where" box. If there is more than one town with this name, a pop-up menu will ask you which one you want. Click "Find." Click "search tips" next to the "Find" button for additional advice. If the name you are looking for is very common, you should use the "expanded search" option. Add the street and house number if you have it to narrow down the search.
Use the function "backward search" if you have only the telephone number but no name or address. Pop the number in the provided box, click "find" and you'll get what you are looking for in seconds.
Get creative if your acquaintance is not listed in the phone book. Call the town hall. Convince the lady on the phone that you are an old friend of your "missing person" and you want to surprise him. Knowing his birthday helps. They will ask you for it. If you know it, they will usually believe you. If not, your luck has run out. German authorities are very particular about data protection and following the rules.
