There are some very clever puzzles in this book, and it is a lot of fun trying to rationalise a seemingly impossible situation. However, some of the puzzles have not an ingenious answer, but an implausible one. It works, but it makes no sense. The best way to back this up is to demonstrate. This is on of the easy puzzles taken from the very start of the book, so giving the answer away is no big deal (but stop reading if you don't want to know it):
One night during the Second World War, an allied bomber was on a mission over Germany. The plane was in perfect condition and everything on it worked properly. When it had reached its target, the pilot ordered the bomb doors opened. They opened. He then ordered the bombs released. They were released. But the bombs did not fall from the plane. Why should this be so?
Some clues are given, and the eventual answer is that the plane was flying upside-down. Now, lateral thinking it might be, but it makes no sense that a plane flying a mission during a war would order its bombs to be released over a target while it was flying upside down. A good puzzle encourages thinking, but anyone who seriously tries to answer that puzzle would discard the given answer as making no sense.
There are still some very clever puzzles to be found here, and the book is worth buying if you want a collection of lateral thinking puzzles, but beware that sometimes Sloane crosses the fine line between ingenious and implausible.