Building Proximity Applications with iBeacon

New book, available in early pre edit form.  Building Proximity Applications with iBeacon - O'Reilly    " ... Information on pinpoint locations can be extremely useful for mobile application developers, but that precise level of detail is difficult to achieve, especially indoors, where GPS signals and cellular service might be weak or unreachable. With this practical book, you’ll learn how to use iBeacons with your applications to determine a user’s location within a few inches and deliver timely, relevant information. ... "