The origins of trade and street directories can be traced to the 17th century but it was not until the late 18th century that they became common and not until the 19th century that they became really useful to the family historian.
They were aimed at the commercial, business and upper classes and it is these sections of society whose names are listed in them. Most of the directories follow a standard format with a brief history and description of the town or village followed by a list of the main inhabitants.
From the middle of the 19th century directories begin to include street directories for larger towns. By the late 19th century the entries for major towns usually comprise a street by street listing followed by an alphabetical listing and a classified listing.
When using directories for family history purposes the directories list only around 40% of the households in any town or village.
By the 20th century the street entries are much fuller with an entry for almost every house. Women are normally only listed if they were householders in their own right or ran their own business.
