Is this movie based on a book?
Yes. It is based on He's Just Not Into You: Your Daily Wake-up Call, a 2005 self-help book by Greg Behrendt, Liz Tuccillo, and Lauren Monchik. However, it actually goes a bit further back to an episode of Sex in the City where Miranda is asking for advice about a guy, and Berger (Carrie's boyfriend at the time) tells her that the guy is "just not that into her." That one line became such a thing that it led to a book, an appearance on Oprah, and now a movie. The book gives advice on how to tell when someone just isn't interested in you romantically so that you can cut your losses and not waste time in pursuit of that person.
How much sex, violence, and profanity are in this movie?
For detailed information about the amounts and types of (a) sex and nudity, (b) violence and gore, (c) profanity, (d) alcohol, drugs, and smoking, and (e) frightening and intense scenes in this movie, consult the IMDb Parents Guide for this movie. The Parents Guide for He's Just Not That Into You can be found here.
Are there any other movies that are based on a self-help book?
Mean Girls (2004) is based on the non-fiction book Queen Bees and Wannabes: Helping Your Daughter Survive Cliques, Gossip, Boyfriends, and Other Realities of Adolescence (2002) by Rosalind Wiseman, founder of the Empower Program, a national violence-prevention program. Wiseman's book describes how female high school social cliques operate and the effect they can have on girls. Sex and the Single Girl (1964) is based on the guide for single women of that title by Cosmo editor Helen Gurley Brown. Although not explicit by today's standards, the book was considered somewhat shocking at the time due to its assumption that single women could be sexually active. Woody Allen's Everything You Always Wanted to Know About Sex * But Were Afraid to Ask (1972) was inspired by a 1969 sex manual of the same name by David Reuben, M.D.
Warum Männer nicht zuhören und Frauen schlecht einparken is based upon the No.1 best-selling book Why Men Don't Listen and Women Can't Read Maps.