According to the information on the back cover the book, the illustrated dictionary is designed for children 5-10 years old, but I would also recommend it for younger children - as soon as they can learn the language. It is also a great learning tool for their parents and grandparents, especially if they do not know Polish fluently - they can learn or re-learn some words with their kids!
I liked the format of the book, it is rather large: 11.0 x 8.5 x 0.3 inches, not really heavy and the edition which I have is in a soft cover. The beginning of the book contains a short explanation of Polish pronunciation. The dictionary has about 500 entries - 5 to 6 at every page. Every entry features the word in English and its Polish equivalent, Polish words also have the phonetic pronunciation.
What I really liked about the book - it is its simple and very clear pictures - every child can easily guess without reading what is a theme of the picture whether it is a noun, adjective or even the verb. The pictures are beautiful and they capture children's imagination. I bought a similar dictionary in Poland for my daughter a year ago. It is addressed rather to a Polish child who wants to learn English, but I thought, this is not really a problem since I know the pronunciation of all these words. The book which I bought in Poland contains also plentiful and colorful pictures but it has some problems. First of all, the pictures are sometimes too complex, they have multiple features and it is hard to figure out what is the main underlying idea behind them. Besides, the pictures are done in the form of caricatures rather that the exact reflection of reality so that the small children have a hard time to understand them. One more reason I recommend The Hippocrene Children's Illustrated Polish Dictionary to all of you, especially these with small children!