With all the talk about learning C first, that is fine with me. But I do not believe that there are any books that do teach me how to do that in (what is now called) xcode. I do have books on C and C++, and they soon start talking how things work in the Borland compiler etc. I do NOT want to know that, I want to learn it in the Mac environment I use, and I welcome this series (but hope a book follows).
A kind word of caution to the author: You write very well, making me understand everything you write. But beware: I've seen a good many books which start that way, but when things get harder, the explanations get shorter and less clear. To get us to program, keep up the current clarity.