No self-respecting chap would dare be caught without a vest or waistcoat covering his dress shirt; it would be like venturing outside in underwear!
The Jackets and Coats run the gamet from Colonial Times to present day. It is best to suit the elegance of the clothing to the impression that you wish to portray whether it be a dapper Victorian Gent or an aristocratic Vampire, a Southern Gentleman, A Dicken's Scrooge or an owner of a fabulous chocolate factory.
