You get an email from a person with whom you have never interacted before and therefore, before you reply to that message, you would like to know something more about him or her. How do you do this without directly asking the other person?  
 
Web search engines are obviously the most popular place for performing reverse email lookups but if the person you’re trying to research doesn’t have a website or has never interacted with his email address on public forums before, Google will probably be of little help.  
 
No worries, here are few tips and online services that may still help you uncover the identity of that unknown email sender.