This is the *only* potty training book that my 3 year old showed any lasting interest in. It caught my eye based on the title, which I hoped would convince my firefighter-adoring son how important it was to use the potty. (Ok... in reality his true love is firetrucks, but the firefighters absorb some appeal through association.) The "storyline," if I may use that term in its loosest sense, introduces several situations where the key players are missing. These individuals--firefighters, construction workers, doctors, zookeepers, and other characters that would be familiar to the average toddler--are otherwise occupied attending to bodily functions. Lifting a flap on the right side of the page reveals the missing person, with strong visual clues to let you know what they've been up to!
Most parents of toddlers are well aware of how much their children like to participate in the reading experience, and my son was quite happily engaged in lifting the flap on each page. I couldn't give this book five stars, because my son did eventually lose interest, but, as I said, it held his interest longer than any other potty training book, and for that, I am most grateful.