A Book on Objective-C
The first edition of Programming in Objective-C was published in 2003 and was aimed at the aforementioned audience of application developers. I wrote the book for the novice programmer, as material already out there (primarily from Apple) assumed previous C programming experience and was not at all directed to novices. I decided in teaching Objective-C that I wouldn't assume previous programming experience—and, in particular, C programming experience. (Many who post on the forums on the Internet are still recommending learning C first before learning Objective-C, and I find that approach a little puzzling.)
The release of the iPhone in 2007 and, more importantly, the release of the iPhone SDK and the opening of the App Store brought a surge of interest in Objective-C, as native applications for the iPhone are written in this language.