This may be the most simple thing in the world for everyone on this board, except for me (I told you I was a bit thick). So if you find this insulting, I apologize.
Last night I was adding some simple transitions in Premier Pro when I inadvertantly hit some button on the left of the timeline (I thought I was collapsing Video Line #4), watching in horror as the whole timeline disappeared.
Not one to panic too quickly, I hit the "Undo" button and nothing happened. I looked into every dropdown menu file that I could and nothing remotely mentioned the timeline.
I looked in "HELP" and immediately figured that the person who wrote the HELP topics and answers should be shot. They may as well be in Latin. Lookus to no availus.
I called my brother who has P6.5 and his interface is different. He has a menu drop down that actually has TIMELINE on it. PPRO doesn't. Go figure. I went to the FAQ page on ADOBE's website. It spoke to the issue directly and the person that wrote that answer should be also be shot . . . after the help guy is shot. Let's be organized about this.
I finally went to the online forums for PRO and found the answer, but this silly mistake of mine cost me 90 MINUTES of searching and trying different things!
So, if you ever lose your timeline in PREM PRO, go to the Bin and find the SEQUENCE 01 file and double click on it, and it magically comes back.
Again, if this is so simplistic it insults someone, I'm sorry, but if I could have found this answer last night, I might have paid for it!!!

(smiley face, just for BIG MOVIE!)