An effective reference letter could mean the difference between a candidate's acceptance or rejection. You may be a person requesting a reference letter, or you may be a person writing a reference letter. In either case, the information in this article can make both requesting and writing the letter easier. A reference letter is essentially the same as a recommendation letter but the reference letter is sent to an unknown employer, whereas a recommendation letter is sent to a known employer. Primarily, a reference letter is used to introduce a person and vouch for his integrity, character, and abilities.