Bakir A. et al. Program the Internet of Things with Swift for iOS: Learn how to program apps for the Internet of Things

Apress, 2016. — 509 p.
The book is a detailed tutorial that will teach you how to build apps using Apple’s native APIs for the Internet of Things, including the Apple Watch, HomeKit, and Apple Pay. This is the second book by Ahmed Bakir (author of Beginning iOS Media App Development) and his team at devAtelier LLC, who have been involved in developing over 20 mobile projects.
Written like a code review, this book presents a detailed "how" and "why" for each topic, explaining Apple-specific design patterns as they come up and pulling lessons from other popular apps. To help you getting up and running quickly, each chapter is framed within a working project, allowing you to use the sample code directly in your apps.