The Confidence Code by Kay and Shipman is one of many advice books for women, girls, and their parents, of the the 21st century, the most popular of which may be Lean In by Sheryl Sandberg , though if the references in this book are any indication, the list might be endless.
The premise of this volume is that confidence is more important to success that intelligence. I find this hard to believe, unless they mean that if you're already smart, some more confidence might be more beneficial than some more intelligence.
The second premise is that women are genetically programmed to blame themselves and expect personal perfection, while men blame anything but themselves and have no concept of perfection. This genetic state of affairs makes confidence, already declared to be more important than intelligence, a challenge for women.
The book is generally optimistic that the stack deck dealt to women is not the last word. Much of this optimism is built on recent brain science that shows plasticity is possible well past puberty, over turning previous thoeries that one's lifetime destiny was determined early in life.
Much research has shown the importance of confidence. One experiment had men outperforming women of a spatial reasoning test. This difference has been well publicized for years. In this case, the experimenters noticed that much of the difference was due to women skipping the hard questions (lack of confidence). When the women were forced to answer every question, they closed the gap with the men. So it was confidence, not intelligence.
A successful women based her confidence on parental advice, "everything would work out -- if I worked twice as hard as everyone." The kicker was that the parent had no confidence in this advice, but "is was the best [advice] they had." I took this as showing the importance of parents in raising girls, something that is both empowering and terrifying.
More brain research explains the different timing for brain development. It is well known that generally girls can work independent in grade school while boys can not. New research has shown that high school girls are challenged in math as high school boys are challenged with Shakespeare. However, by their twenties, the gap disappears.
One last gem. No book that mentions parenting can avoid complaining about the self-esteem fiasco of the 1980s and 1990s. You know the approach where everyone was a winner and everyone's effort was perfectly wonderful. The confidence spin here is that confidence comes from overcoming significant challenges, not from praise.
To spite the obvious sexist predisposition of the two (female) authors, the book contains lots of useful advice for anyone wanting more confidence.