Telephone directories are a useful way of identifying geographical "hotspots" for a surname, as well as for targetting people to write to speculatively.

Remember that many people prefer to be ex-directory, so this is just one tool you have available to identify people you want to contact.

Making direct contact with people in this way can be a costly method.

It is important to know why you are ringing (or writing to) someone who is listed: make a note of what you want to say, in the same way as you would in preparing a speculative letter. Be prepared for the fact that some people will mistrust your motives in contacting them, and may react to you as if you are telephone salesperson!