The document discusses the importance of sending a thank you letter after a job interview. It provides 5 key reasons for sending one: 1) it shows professionalism, 2) it allows you to further communicate with and network with the interviewer, 3) it allows you to provide additional information or clarification, 4) it should be sent to all important people involved in the hiring process, and 5) it should be sent within 24-48 hours of the interview. Examples of thank you letters via email and formal letter are also provided.