This series of books provides wonderful insights into your child at every age. Though originally written long ago, which makes some of their advice a bit outdated, the observations have been "spot on" for each year of our children's lives, and therefore very helpful parenting tools.
Although these books haven't been updated in years, the mind of a child at their various ages and stages of life has not changed. These books are very helpful in understanding the development of you child and providing useful tools to meet these stages head on and adapt to them. Invaluable resources for your book shelf.