In two daring, dazzling new novels, authors Jane Smiley and Lionel Shriver contemplate morality and sexuality. Shriver’s The Post-Birthday World (HarperCollins) begins at the moment one woman decides whether or not to cheat on her long-term partner. Smiley’s riveting Ten Days in the Hills (Knopf) follows a group of California "beautiful people" holed up in Hollywood in the early days of the Iraq War, wondering about the future and one another.MORE: Could you have written these books 15 years ago?Shriver: I couldn’t have. This is the kind of book you can write only when you’re older. One editor I met with said that for this novel to be relevant, Irina, the protagonist, needed to be much younger. But I like that Irina is over 40 — the romantic stakes go up past 40. Your choices may end up being permanent.Smiley: In the great English tradition of the novel, the protagonists are young and the novel ends when they marry and get some money. In the French tradition, the story begins early in their marriage, then one has a terrible affair and somebody dies. So the idea that sexuality and love and romance continue as the characters get older is fairly new. But I’m 57, and I don’t feel desexualized by age; I didn’t meet my current partner, who is the love of my life, until I was 49, which means that we’re in some ways romantically similar to much younger people. But we’re also contending with his heart condition, my deteriorating joints, and whether I’m going to be gray or blond.Shriver: As a reader I am increasingly interested in stories of relationships that have already begun and far less interested in that youthful question of will they or won’t they get together. Smiley: Because you look back and you say, "Oh, they’ll find somebody."MORE: Do we overemphasize the importance of choosing a partner?Shriver: It isn’t nearly as momentous as we like to portray it. That sounds so anti-romantic and I don’t want to insult my husband, but we do tend to resort to new partners partly as a source of transformation — and we wind up being the same person. Smiley: My experience is the exact opposite. I’m in a committed long-term relationship, so he is essentially my fourth husband. I chose my earlier partners in a very arbitrary way; I’m over 6 feet tall, and if someone was willing to ask me on a date, I’d say, "Let’s get married." But when I found my current partner, he was much more resistant than the earlier ones. I had to be patient; I had to allow him his freedom. My experience of myself in relationships changed completely around the time I was 49, 50, 51. The whole nature of relationships shifted in my mind from "gotta get married" to "let’s see what happens." To me that’s the unique pleasure of a relationship in the second half of your life. There’s a lot less pressure.MORE: These are pretty sexy books, although in different ways. The Post-Birthday World is infused with longing and emotion, while the sex in Ten Days can be intense or funny. Has the way you’ve written about sex changed as you’ve gotten older?Shriver: It’s more honest. Despite our ostensible liberation, communication between couples is not necessarily easier. An awful lot of people imagine that everyone is having great sex but them. I was trying to indicate that they’re not alone. We’re all dealing with some kind of inadequacy, despite both partners’ good intentions.Smiley: Male writers, especially older ones like Norman Mailer, have been exploring male sexuality for generations; women haven’t been.MORE: Do you think the fact that you’re women writing about sex will affect the way these books are received?Smiley: Who knows? I truly enjoyed writing this book. So whatever the response, who cares?Purchase The Post-Birthday World Purchase Ten Days in the Hills Originally published in MORE magazine, March 2007.