reviewed by Christian Fisanick (confirmed purchase)
Rating: ★★★★★ (Date Added: Tuesday 04 June, 2019)
Old, but still exceptionally good, book test. This is worth a few times more than a tenner. Buy it, download it, and you don't even need to print it out in book form. Keep it as a PDF on your phone. (There is nothing unusual about having books on phones any more.) And this is not an app but a regular PDF file with the dirty work built in. It takes about a paragraph to explain the method, which is great and quite deceptive. You will love this and use it in impromptu situations. I know that I will.