I believe that many procedural programmers have shy ed away from OOP because as the author stated, it is an abstract concept. It can be somewhat hard to grasp if you work exclusively within a procedural environment. I was a hold out for many years until I finally had a basic idea of what OOP was all about. Now, I can't see myself ever going back. It is important for php developers to have a firm grasp on the procedural environment but in order to grow as a developer OOP is an absolute must to incorporate into one's knowledge base.