I have a number of preferred brain teaser books that I have collected over the last couple of years - they're fun to do, and include a variety of brain teasers. I now have a favourite to add to this list! This Mammoth Book of Brain Teasers doesn't fail to impress by offering logic problems, optical challenges (my favourite)and other number/word teasers. Best of all, is that the content is all original, presenting completely new challenges, with both easy, medium and hard problems - so you can feel happy to complete some quickly, whilst the more demanding ones leave you deliberating possibilities long after you've put the book down - if you can bring yourself to leave it for that long! Great fun - an essential buy for any lover of good brain teasers.