Collaborative novels are often frowned upon — literary types consider them the stuff of movie tie-ins or ghostwriters. But why exactly should that be? When you have one exceptional mind, why not double or even triple your pleasure and/or fun? The tighter-knit circle of SF masters hasn't embraced working together en masse, but there's a small treasure trove of classics with two names on them.Scholars often point to Mark Twain's collaboration with Charles Warner Dudley, The Gilded Age, as a starting point for collaborators. With the advent of the internet and inexpensive long-distance telephone service, long distance interchanges enabled more connections between writers - with better manuscripts the pleasant result.

The Book: Frederik Pohl and Cyril M. Kornblut's 1953 classic The Space Merchants How Was It Forged?: The two were both members of the New York City writer's group the Futurians. The success from the venture inspired Pohl to pursue a number of other collaborative ventures, just as the book's failure might have inspired the reverse. Pohl's work with Jack Williamson produced the Undersea trilogy of the 1950s and ongoing efforts with numerous other offers. Why Is It Worth Reading?: At under 200 pages, Pohl and Kornblut may have come up with the best form if you hope to speak to your writing partner after the collaboration. The novel's ostensibly about a man selling a trip to Venus, and it gets more enjoyable from there. More of a novella than novel, The Space Merchants may be a little dated, but it comes by its considerable reputation honestly.

The Book: Larry Niven and Jerry Pournelle hilarious 1976 co-production Inferno How Was It Forged?: Ringworld author Larry Niven just has the engaging personality and intellectual curiosity required for healthy collaboration, it would seem. Inferno followed the success of their initial joint effort two years earlier, The Mote in God's Eye. Niven's experimentation hasn't always pleased his critics though: ""I've been advised to kick the habit," he quips on his home page. Why Is It Worth Reading?: We're always a sucker for an entertaining twist on Dante's Inferno Nominated for both the Hugo and Nebula that year, Inferno has all the right pedigrees. It will get a sequel later this year, one that claims to depict Sylvia Plath in Hell as a major character.

The Book: SF giants James Patrick Kelly and John Kessel's 1985 collaboration, Freedom Beach. How Was It Forged? The last collaboration between these two giants of the genre was Rewired: The Post Cyberpunk Anthology, but the two friends churned out Freedom Beach in 1985 after meeting at a WorldCon. Kelly eschews a solitary creative process by workshopping most of his writing, and Kessel's tendency to favor the short story interested him in a longer project. Why Is It Worth Reading?: A psychological mystery novel with considerable dream-life may not be the most commercially viable concept, and Freedom Beach ascends to neither of the heights either author achieved on his own. With that said, there is much that is rewarding here, although you might enjoy their short take (with Jonathan Lethem) on Sturgeon's Law, Ninety Percent of Everything. Kelly describes that collaboration:

More recently we've been collaborating with Jonathan Lethem, who is very skilled at developing the conceit of a story. On our last collaboration, "Ninety Percent of Everything", Jonathan and I were stuck maybe two-thirds of the way through the novella and we handed it off to John, who came up with a marvelous ending.

The Book:Interface by Stephen Bury (a pseudonym for Neal Stephenson and J. Frederick George) How Was It Forged?: George, Stephenson's uncle and a practicing historian, bugged his nephew with an idea to write a Tom Clancy-like thriller. Originally released under the nom de plume Stephen Bury, the book was largely unread until Stephenson's popularity exploded and it got a much-deserved reissue. Why Is It Worth Reading? Many have sampled this Manchurian Candidate-styled novel about a Midwestern governor with a microchip and found it a worthy technothriller, including Cory Doctorow.

The Book: 1995's monster in a museum smash Relic by writing team Douglas Preston and Lincoln Child How Was It Forged? The now long-running Lincoln Child and Douglas Preston partnership was announced here, and the successful union has continued even though Child won't board an airplane and one are often many miles away from the other. Since hammering out the finer points of Relic, the two are now a bi-coastal team. Why Is It Worth Reading?: A museum setting (based on the Museum of Natural History where Preston worked for years), inventive monster, and scientific grounding distinguish Relic.For those who don't know the story, it's a weekend full of pleasant entertainment in the hands of Louisiana detective Pendergast. If you are looking for a scare around Halloween, however, their 2002 Pendergast novel The Cabinet of Curiosities ranks with The Relic as their best. Child will return to horror-flavored science fiction with next January's Terminal Freeze.

The Book: Arthur C. Clarke and Stephen Baxter's "A Time Odyssey" series How Was It Forged?: The British Baxter grew up admiring Clarke, and in his early efforts styled himself similarly. The two met when Baxter went to interview Clarke, and hit it off. Until Clarke's death, the two communicated by e-mail and phone. As Baxter put it: "We began with outlines from Arthur, which we worked up into a decent proposal, then got down to planning the chapters. We resolve disputes by arguing until one of us gets a better idea." Why Is It Worth Reading?: The first novel in the series, Time's Eye, combines compelling adventure with the deep conceptual grasp the two are known for. With the recent Elizabeth Bear project and collaborative universes like Orion's Arm, the future of collaboration may well encompass more than two or three minds.