As an adult, I loved this book. Each page has a beautiful, artistic illustration on it with a single word description. The nostalgic style of the illustrations is a refreshing change from most contemporary children's books.
When read through the book, you'll notice an association between the figures on the pages. For example, on the left page will be an illustration of a man looking through a microscope with the word BIOLOGIST, while on the right page there will be an illustration of a man looking though a giant telescope with the word ASTRONOMER. Initially the associations are easy and obvious, but as you progress they begin to become more complex.
As a parent, I still love the book, but I can see how others might be hesitant. There are illustrations that other parents might be uncomfortable explaining to their young children. For example: CORPSE, AMPUTEE, EXECUTIONER.
Every parenting style is different, but I will have no problem trying my best to explain these figures to my daughter when the time comes.