"Walking on Eggshells" is basically the "BPD 101", it will usually be the wake-up call for people that "Wow, there's a name for my crazy relative? This sounds so accurate to my life!". It's not the best book out there, but it's the most famous by far; and it will groom you towards accepting DBT/CBT is the answer to all Borderline problems (it's not always, but a sizable percentage of people say it's the best improvement they've seen).
Is your daughter in the 15-25 range? That's certainly when it's usually first noticed and a name can be put to it. One problem with diagnosing BPD in younger children is that many of the traits of BPD are normal for children; all children have unstable senses of identity as they build one, nearly every 7-year old lacks long-term thinking, etc.