This is a highly populated network of professionals and others in business across the globe. You can search over 20 million profiles on LinkedIn for people.
There is a member directory accessible from the bottom of the page. You can browse this by letter, narrowing down the range of names as you go. At the bottom of the directory you’ll find profiles of people matching that name. Registration is required to access the complete profile of someone. Note that it is free to register.
There is also a first and last name search which can narrow down the profiles quickly.
An alternative option is to narrow down members by country and region. If the person you are looking for has a common name, using additional fields to narrow your search can be helpful.
LinkedIn provides a means of contact as well as providing details on peoples current place of work. This can be handy when you wish to make contact with someone.