It's exactly what the title sounds like. The editors looked around to find bisexuals -- and those who do not identify as bi, but who are not monosexual -- from around the world to write on various topics related to our sexual orientations. This book is mostly a compilation of what others have contributed, with some notes and comments provided by the editors.
The book is four years old, but it presents what I suspect is a good snap shot of what bisexuality looks like in the world. It shows what being bi means to us, what we do about our orientation, and how we interact with the world. Since we are such a diverse group there is of course a lot of variety. Some who have always known, others who took some time to figure it out. Monogamous bis, those who are polyamorous, and also those who do outright cheat. Some who call themselves bisexual, others who don't label themselves. Some who have friends and family that are accepting, some who aren't so lucky. And of course, the chapter where bisexuals are defining what the word means has differing opinions.
If nothing else, this book shows the variety in the bi world. And that it's pretty pointless to make assumptions and stereotype people, since yeah some will fall into those stereotypes, but many others don't.
On a more personal note, I had to step away from the book for a little while. It was painful for me to read about those who take a while to figure out they're bi because of initially believing that bisexuality doesn't exist. It happens, and is inevitably going to be part of any work like this, but I found it unpleasant to read about. Probably because I've been there myself. I suspect that any bisexual will find parts that make them uncomfortable, though this isn't meant as a warning to avoid it.
I have to say, it's a good book. I especially have to recommend a small section at the end titled If You Think Your Child May Be Bisexual by Robert L. Barton. It looks excellent for anyone who has just found out that a loved one is bi, but is written to provide recommendations for how to parent a bisexual child. Barton points out some issues that bis often face and which parents should be aware of, he clarifies a few common misconceptions, and encourages both learning about bisexuality and communication with the child.
Although I would not suggest Getting Bi as the only book for someone who is learning about bisexuality, it is certainly a good option. And it provides many other resources to look into, from fiction and non-fiction books to organizations and websites.