He's Just Not That Into You, by Greg Behrendt and Liz Tuccillo, Simon Spotlight, 2004.
I've been married, more or less happily, for a little over ten years now, so this book wasn't especially relevant to my life now. I did, however, date for about twenty years before I got married, and I WISH this book had been around then.
Yes, the advice is simplistic and fairly obvious, but that doesn't mean that single women don't need to hear, or rather, read it. I wasted a lot of time making excuses for the men I was dating. It was very hard for me to be a single women when I was in my 30s, so I understand the excuses very well, but I did myself, nor the men, any favors by making the excuses.