My Son is only 2.5 yrs old, but loves puzzles and also likes to use the glue and paste. Since it was too much for me to keep on buying wooden puzzles, I got this book even though the age range was different. He is enjoying them immensely (though I have to do the cutting for him).
Since the puzzle pieces and the pieces in the solution page come numbered, with the first puzzle, he simply started matching the numbers and got it right in a sec! Since then I have him solve the puzzle outside on the table and then make him stick the pieces on the solution page. I feel this could have been avoided.
One improvement would be to make it spiral bound so that you dont have to hold the pages while the kid is working!