Our class is on edexcel exam board AS CHEMISTRY . My friend was only reading CGP AS Chemisry revision guide he didn't even bother to buy a textbook for syllabus and I did most of my revision from the actual textbook. well result is he got 95% for his exam =P and I have got 71%. However his actual chemistry knowledge doesn't extend further that the revision guide but as you can see results don't lie Revision guide alone will do the trick. (2010 Jan exam Unit 1 ) (btw added revision guide to my textbook/flashcards/notebook revision ^^ not gonna fail miserably again on resit)