A letter of gratitude is a letter that is used when one person/party wishes to express appreciation to another. According to Harvard Medical School gratitude is a thankful appreciation for what one receives – tangible or intangible — as they acknowledge the goodness in their lives. In that line letter of gratitude is intended to communicate in written acknowledgement of what one has received. Letters of gratitude, or often called thank you letters - are rarely hand-written, except in cases in which the addressee is a relative or friend. Rather letters of gratitude are usually written as formal business letters, that follow stand form. Most often letter of gratitude is written to thank someone for: Provided service;Demonstrated professionalism;Good business offer;Positive or negative feedback;Provided care by