On this installment of ST Medical Monday, our guest is F. Diane Barth, a longtime psychotherapist based in New York City. She joins us to discuss her new book, "I Know How You Feel: The Joy and Heartbreak of Friendship in Women's Lives." As was noted of this readable and useful study by Kirkus Reviews: "A psychotherapist offers advice about how to be, and keep, a friend. Barth, whose Psychology Today blog frequently focuses on women's friendships, draws on interviews with diverse women to examine the 'magical, meaningful, and surprisingly difficult' connections they make with friends. Friendships, she writes, 'can make us feel simultaneously special and outcast, loved and unlovable, vulnerable and strong, helpful and useless, angry and happy, alone and lonely, supportive and held.' From the testimony of her interviewees as well as research, she finds that women's friendships often are characterized by emotional intimacy, trust, respect, and honesty. But friendships take many forms: some women consider friends to be occasional companions rather than confidantes; some want friends to visit often, while others are fine catching up on social media. Some women obsess over not having a large enough number of friends (an obsession exacerbated by Facebook), while others feel happy with just a few. 'Research has found that friendships support mental and physical health in a variety of ways,' writes the author, but 'the number of friends is less important than the role they play in your life'.... [This is a] friendly, supportive guide for navigating relationships."