Number Book is a social app that lets you use your phone number to find out all the information for any contact in your address book. In this way, you can complete every profile with information directly from your contacts and see their basic info when they call. Number Book works in a very similar way to WhatsApp, except this app lets you link your profile to other social networks to find more friends (even though they need to have this app installed as well to be able to communicate with you). In practice, the chat is identical to other similar apps, with emoji and options to attach images, audio, video, and GPS information, besides incorporating other features similar to what you can find on WhatsApp or Telegram. On the other hand, with Number Book you can also send texts, block incoming calls, call your friends without having to dial, and share contact information on other apps.