iPhone User Guide for iOS 9.3
This book can be downloaded and read in Apple Books on your Mac or iOS device.
Here's everything you need to know about iPhone, in a handy digital format. Get to know iPhone and discover all the amazing things it can do, and how to do them. It's the definitive guide for getting the most from your new iPhone, straight from Apple. The iPhone User Guide is an essential part of any iBooks library.
Hard to find info.
There is neither a table of contents nor index, making it hard to find a section of interest.
Font Too Small!
Font for IDing parts of iPhone is way too small and page can’t be enlarged. It isn’t young users who need the “how to” stuff, it’s older users like me who find tiny fonts frustrating. Vet your stuff with someone older before you sell it. Small fonts are really dumb in any user manual or guide for electronic devices.
iBook on OS 9
Lots of good info. Some lack of clarity for beginners. Should be able to read it on a non-Apple device. Especially for people over 40. I can't judge the accessibility options, but it's great Apple included so much help in that area.