Simpler Contacts is a software that replaces your traditional address book with another that has a more elegant and minimalistic interface where you can keep track of all your contacts.
The first thing you'll need to do when you use Simpler Contacts for the first time is combine all the duplicate contacts in your current address book (something that happens more often than you'd think). After merging all the duplicates, you can begin to use all the app's other features.
One of the most interesting features of Simpler Contacts is the option to back up your address book and store it on any cloud service you have installed, like Dropbox or Google Drive. Another great feature lets you set up smart filters so you can remember birthdays or someone's profession or company position, for example.
Simpler Contacts is a good alternative to the default address book and has not only many interesting features but also a nice-looking and well-designed interface.