This book does have a list of good problems. If you're trying to just experience some thought provoking problems which don't occur in the curriculum/syllabus then it's well worth it. If you're preparing for some competition or gaining knowledge, then i wouldn't reccomend it (unless you're really widening your repertoire). These problems are good but, as stated in the book, maths problems have a shelf life, many of these in the book have expired. A useful resource list for more material is extremely helpful though, in certain solutions it refers to these books and gives you a brief sentence of information regarding subjects, ie number theory, which does help massively. However, if you're completely dumbfounded by a problem, you may have to develop your thoughts when studying the solutions. But that may be unlikely due to the mathematical capability of people buying this book
The book has the National Mathematics Contest papers (for GCSE students) from 1988 to 1996, with solutions and comments. A definite must for those who enjoy a wide variety of mathematical puzzles not needing a maths degree!