This is a book about AS (advanced subsidiary) and A (advanced) level Mathematics. It aims to fit in with the WJEC GCE Mathematics Specification (2009 onwards) syllabus but is not endorsed by WJEC. It should be useful as a revision guide or to find alternative explanations to the ones in your textbook. It assumes you have already done GCSE Mathematics. While it is aimed at people studying A-levels, it may be of interest to others in general. More information about A-levels can be obtained from the A-level article in Wikipedia.