As a courtesy, this is a full free rendering of my book, Programming iOS 6, by Matt Neuburg. Copyright 2013 Matt Neuburg. Please note that this edition is outdated; the current books are iOS 10 Programming Fundamentals with Swift and Programming iOS 10. If my work has been of help to you, please consider purchasing one or both of them. Thank you!

Chapter 40. Epilogue

You may go, for you’re at liberty.

W. S. Gilbert, The Pirates of Penzance

This book must come to an end, but your exploration of iOS will go on and on. There’s much more to know and to discover. A single book that described completely, or even introduced, every aspect of iOS programming would be immense — many times the size of this one. Inevitably, severe limits have had to be set. Having read this book, you are now in a position to investigate many further areas of iOS that this book hasn’t explored in any depth. Some of these areas have been mentioned in individual chapters; here are a few others:

OpenGL
An open source C library for drawing, including 3D drawing, that takes full advantage of graphics hardware. This is often the most efficient way to draw, especially when animation is involved. iOS incorporates a simplified version of OpenGL called OpenGL ES. See the OpenGL Programming Guide for iOS. Open GL interface configuration, texture loading, shading, and calculation are simplified by the GLKit framework; see the GLKit Framework Reference.
Accelerate
Certain computation-intensive processes will benefit from the vector-based Accelerate framework. See the vDSP Programming Guide.
Game Kit
The Game Kit framework covers three areas that can enhance your user’s game experience: Wireless or Bluetooth communication directly between devices (peer-to-peer); voice communication across an existing network connection; and Game Center, a networking facility that facilitates these and many other aspects of interplayer communication, such as posting and viewing high scores and setting up combinations of players who wish to compete. See the Game Kit Programming Guide.
Advertising
The iAD framework lets your free app attempt to make money by displaying advertisements provided by Apple. See the iAD Programming Guide.
Purchases
Your app can allow the user to buy something, using Apple’s App Store to process payments. For example, you could provide a renewable subscription, or offer to unlock advanced app features. See the In App Purchase Programming Guide.
Newsstand
Your app may represent a subscription to something like a newspaper or magazine. See the Newsstand Kit Framework Reference.
Printing
See the “Printing” chapter of the Drawing and Printing Guide for iOS.
Security
This book has not discussed security topics such as keychains, certificates, and encryption. See the Security Overview and the Security framework.
Accessibility
VoiceOver assists visually impaired users by describing the interface aloud. To participate, views must be configured to describe themselves usefully. Built-in views already do this to a large extent, and you can extend this functionality. See the Accessibility Programming Guide for iOS.
Telephone
The Core Telephony framework lets your app get information about a particular cellular carrier and call.
Pass Kit
New in iOS 6, the Pass Kit framework allows creation of downloadable passes to go into the user’s Passbook app. See the Passbook Programming Guide.
External accessories
The user can attach an external accessory to the device, either directly via USB or wirelessly via Bluetooth. Your app can communicate with such an accessory. See External Accessory Programming Topics.