I've just finished this and it's a real eye opener. I read BabyCalm and attended the classes, and after a year I feel like a pretty confident parent of a baby. With the toddler years approaching I felt the need to be prepared, so this is the first book I went for. What it does first and foremost is provide facts, not opinions or anecdotes, but actual scientifically verified facts about toddlers; how they are developing, why they do what they do, and how we as parents can help them along.
The science on offer is broken down and explained in a way anyone can understand, but that's not to say it's "dumbed down", it isn't. It's explained clearly and succinctly so anyone can read it, understand it, absorb it and put it to use in your life. Most importantly, it makes you think! It also, again very clearly, is lay out what is normal for a toddler; it may not be societies idea of a 'good' toddler (i.e. compliant, quiet etc) but it's just normal. Reading that is incredibly reassuring and alleviates all kinds of parental stress and anxiety.
What it doesn't do it 1) claim to know your child 2) give you a list of do's and don'ts, which if you can't achieve makes you feel like a failure and 3) set up your toddler and some kind of adversary (the impression I get from many 'child experts') who's out to ruin your life.
If you have a toddler, get it. If you have a baby who's around 1, get it. Arm yourselves with knowledge, and knowledge derived from science not habit and authority.