These books are all excellent at helping us as adults gain the confidence to talk to our young kids (by young I mean about 4 years in age onwards) about important body-related stuff.
I would suggest reading them in a certain order though, as they each build on the other... Up to Babette Cole's brilliant stick-person illustration of sex on a space hopper!
Here's the order in which I chose to share them with my eldest...
I would also like to read...
Where Willy Went by Nicholas Allen (the author who brought us the brilliant Santa Claus Needs a Wee)
and
*I've not read these two yet, I've just heard good things*
For older kids - upper years of Primary school - the following Usborne books are great...
What's Happening to Me? (there is a boy edition and a girl edition - it's worth getting both)
So, happy reading together!