I agree with the Pinky McKay recomendation.

She has also written "100 ways to calm the crying"

Another fantastic one is "The Science of Parenting" by Margot Sunderland. I'm in the process of reading that and it is great. it really goes into the brain development and how your behaviour can affect your child. It also gives practical tips on how to use your child's developmental stages as tools in your parenting. Working with your child rather than agains it. I can't recommend it highly enough. It's scientifically minded but easy to read.

Then there's "Gentle Birth, Gentle Mothering" by Sarah J Buckley. I looooooved this book when I was pregnant. It was actually recommended to me by my midwife. Again, it has some scientific aspects in it, but very easy to read. but it does focus more on pregnancy, birth and the immediate baby stage. Although it does have a little about toddlers as well. You can read quite a lot of her articles from the book on her web page. Just google her name.

I haven't read Dr. Sears' book, but I have heard some good things about it.

Then there's "The Continuum Concept" by Jean Liedloff. I haven't read it, but I have read about it and find it intriguing. It's on my list.

I'm sure there's lots of others, I just can't think of them. I can't help you with tweens. But I can imagine that it must be soooo difficult.

Sasa