I've been enjoying doing Sudoku's for about a month. A friend gave me this and it is the first tips book I've seen. I don't consider myself as someone with some kind of Spock level of natural logic but was amazed to flick the book, cover to cover, and discover nothing I hadn't worked out myself in the first couple of hours of playing Sudoku. Very, very simple tips are, fair enough, explained well inside, but unless you are logically clueless this is too elementary for even a basic beginner.
My main gripe with the book is that it catogorises 'difficult' and 'super difficult' Sudokus (which is always open to interpretation) which, from every other source I've seen, the 'difficult' are comparable with medium and 'super-difficult' with the milder difficult ones you find in newspapers etc.. Only puzzles, 199 and 200 offered what I would consider a genuinely hard challenge. I believe the reason for this is that the tips covered in the book are not enough to solve a 'real' hard sudoku, so they have produced the book this way on purpose. Cynical.
Two stars as the there are 200 puzzles, which, at the price is not bad value, just look elsewhere for a really in-depth book which covers far more techniques than this.