GCSE (General Certificate of Secondary Education) - In Britain school kids have two exam levels. We usually take between 6 to 8 subjects at GCSE level at 16 years old, and 3 to 4 subjects at "A" (Advanced) level at 18 years old. The grades you get at "A" levels determine if you get into university, and what you can study.
"On the beach" was a novel written by Neville shute. If you haven't read his novels I would highly recommend them. Brings back memories for me of the cold war, and the MAD scarnerio. Spine-chilling stuff.