If you are looking to access the device contacts on Android and IOS with Delphi XE8 Firemonkey here is an upgraded wrapper library that does just that. I originally had this created for XE5 and another developer combined the Android and IOS wrappers into a single class. This upgraded version gives you access to both in Delphi XE8. This library is free with source code. There is no support provided for Windows or OSX contacts. First name, last name, phone number, and email address are all exposed by the existing functionality. Demo source code is included. If there are other fields you want to access or you want to write to the contacts you will need to add those yourself. For Android you will need to go to Project|Options|Uses Permissions and add the Read Contacts permissions. For IOS you will need to go to Tools|SDK Manager, select the IOS SDK, and add the AddressBook framework to the list. Be sure to update the local cache after you do this. This library should also compile in Appmethod.
FMXExpress.com has over 700 tips and tricks for building cross platform apps on Android, IOS, OSX, Windows, and Linux with a single codebase and single UI using the FireMonkey framework found in Delphi and C++Builder.
FMXExpress covers top cross platform secrets for FireMonkey in C++Builder and Delphi XE5, XE6, XE7, XE8, Seattle, Berlin, Tokyo, Rio, and Sydney.