a question about the PHP manual

Hello, As I'm studying, and learning, PHP, I use certain resources again and again. A few books I've bought, some web sites, this mailing list, and the PHP manual. I've taken the often repeated 'RTFM' to heart, and I attempt to google or RTFM before considering a post to the list with a question, but now I have a question about the manual itself. I've noticed that most of the replies to the questions on this list, when they refer to a part of the manual, point to the same few sections over and over. Such as arrays, strings, sessions, objects, and a few others. My question is this, when I'm reading the manual, is just that I should be concentrating on a few sections (and if so, which?), or should I be giving equal attention to all the sections, including some (I suppose) I might never use. Thoughts? thanks, William