Address Book does save the details!
You can import all of the contacts stored on you device and additional information that you define. You can add custom fields to contacts, addresses, phone numbers, and email addresses.
Define your own custom fields: Custom fields can be added to contacts, addresses, phone numbers, amd email addresses.
Filter Contacts Quickly and your entire list of contacts if the first thing you see when you open Address Book. The filter bar allows you to quickly find the person you're looking for. Tap on the contact and then can quickly navigate to their address, call their phone number, send them an email,
Address Book can be used as an Agenda, keeping track of business clients, customers, friends, family, and more easy way to keep the information at your finger tips.