|One of the rough illustrations I've knocked up in my time|
However I have recently come across a situation where illustrations can have a painfully negative effect. This was in the Steven Hawking book The Grand Design, which has caused so much fuss because of Hawking's pronouncements that God and philosophy are no longer necessary. The illustrations in this book are beautiful - but I strongly suspect they were put together by an art editor without consulting the authors, because two of them are plain wrong.
At one point we read about a solar eclipse and how it is visible 'only in a corridor on the earth about 30 miles wide.' That's fine - but the accompanying illustration shows the moon throwing a shadow covering a fair proportion of the earth's hemisphere. This shadow certainly must be 15,000-20,000 kilometres across. Whoopsie!
A little later, there's quite a good explanation of the basics of relativity, but the illustration, showing a bouncing ball on an aicraft as seen from the plane and from the ground is totally confusing. The reason is the view from the ground shows the ball moving diagonally. That's fair enough. But it is shown moving diagonally with respect to the plane, rather than with respect to the ground. And that's just wrong. It's a Relativity 101 fail.
There is no way the authors could have made these basic errors, so I can only assume they never even bothered to look at the illustrations. A good lesson here. If you ever get paid so much for a book you don't need to look at the illustrations, it shouldn't stop you from doing so.