In A Nutshell
Virginia Woolf wrote Orlando: A Biography in 1928, following the publication of acclaimed novels Mrs. Dalloway and To the Lighthouse. Orlando is dedicated to her friend and lover Vita Sackville-West, and fictionalizes the Sackville family history and Sackville-West's own flexible approach to sexuality and marriage. Orlando also works as an enactment of Woolf's prescription to biographers, in her 1927 essay, "The Art of Fiction" and "The New Biography," to "yoke truth with imagination" (source). Woolf argues for increased truth in fiction and increased fiction in truth. In other words, she seems to be arguing for a novelistic approach to biography. (For more on this, check out Orlando's "Character Analysis.")
Orlando has been popularly read as an example of lesbian or bisexual fiction. While Vita Sackville-West's son and biographer confirms that Woolf was writing about Sackville-West's sexual adventures with both genders, the fantastical trappings of the story (the gender switching, voyages abroad, etc.) meant that the censors of the day wouldn't necessarily have noticed the risqué content. Furthermore, the book has often been dismissed as a less serious work than Woolf's previous novels. However, we find the novel 1) awesome, and 2) about so much more than ambiguous and shifting sexualities. Nothing is solid in this novel, not history, writing, or even character names. It's explosively experimental, and gender roles are just one of its many targets.
Why Should I Care?
It's one of the first things we learn: there are boys and girls, and you are one or the other. If you're a girl, your parents dress you in pink, and if you're a boy, your parents dress you in blue. Don't get us wrong, there're plenty of girls out there who wear blue, and lots of guys sport some fetching pinks. We all come to realize that these categories aren't hard and fast, especially in this day and age. But still, most people believe that there is some biological basis for thinking that women are different from men. You've probably heard stereotypes: women are more nurturing; men are more aggressive.
Orlando would say to this biology business: no. Or maybe the novel would argue that our private parts influence our public behavior, but in a perfect world, they wouldn't.
What we have here is a fabulous fantasy of what life would be like if there were a third option. Orlando has been both a guy and a girl, and so Orlando understands the nature of her former lovers (especially Sasha) and present husband, Shel. What Orlando learns would have been hidden from her if she couldn't move between bodies and genders.
Orlando uses gender to imagine what it would be like if our social identities were less bound to our bodies. Would there be gender hierarchies in our society if we could really experience how the other half lives?
Orlando is making an argument for the power of imagination: sure, we're all bound to our own bodies, and not many of us will be lucky enough to live 400 hundred years, like Orlando does. But we all have the capacity to empathize with others in the pursuit of deeper truths about the human experience, unbounded by gender, race, and place. These physical factors can't be done away with, and Woolf keeps coming back to Orlando's biology as a recognition that you can't always ignore your body. But you can use your imagination (possibly in conjunction with a good book) to try on someone else's experiences for a day.