How to Email a Professor

NEVER begin with "Hey" or similar. Spell your professor's name correctly. Generally speaking you should use "Dear Professor Last-name." Do not use "Mr. Last-name", especially when the professor has a PhD, where the only alternative honorific is "Dr.". If he or she signs the reply with a first name it is still best to address her/him as "Professor" in an email. Do not use the professor's first name unless you have been explicitly invited to do so.