The art of letter-writing may eventually be supplanted by the email or text message, but it is far from dead.
On many social occasions, a letter is infinitely preferable to an email, text or phone call - when extending an informal invitation, when thanking a host for hospitality, when congratulating someone or wishing them well.
Thank you letters are always better than emails and texts, they communicate both care and deliberation. Finally, letters of condolence are absolutely de rigueur.
For a comprehensive guide to addressing people with titles, as well as other correct forms of address, please click here