"In this fun-filled book, kids can not only follow the imaginative exploits of these two boy inventors, but also share the fun of building a variety of wind-up robots just as Phineas and Ferb might do. Each book includes a wind-up robot toy base and three sheets of punch-out pieces of different heads, arms, and bodies. Kids can mix and match them to make all kinds of funny, personalized "Brobots", as Phineas and Ferb like to call 'em."--Amazon.com.