Puzzles present many benefits for children as they develop.
Children usually start out with simple knobbed puzzles that are outlines of simple shapes that fit into corresponding board cutouts. From there they go to more complex silhouettes of real world objects that take more consideration.
Three basic skills to be built with puzzles:
Physical skills - from holding puzzle pieces and turning them until they fit
Cognitive skills - as they solve the problems of a puzzle
Emotional skills - they learn patience and are rewarded when they complete the puzzle