It's generally thought to be a novel-length love-letter to Virginia Woolf's female lover, Vita Sackville-West.
It really is a surprisingly modern and bold book for something that was written in 1928 - and says a lot about the interaction between the sexes, as Orlando finds that her new gender is subject to different social restrictions than her old gender.
I love the way that Orlando suffers from the 'affliction' of literature - and the discussion of poets, writers, and writing, that this provokes at various points.
But then, I love it when books talk about books - reading, writing, whatever. It appeals to my inherent bookishness.
And the writing itself draws you on - this was one of those books where 'just one more page' became a meaningless mantra, because one page, more often than not, turns into ten, or twelve...
Not so great bits:
The seemingly rule-less, accepted-on-face-value, nature of the surreal aspects just won't appeal to everyone - but I liked it.
I do like the surreal aspects of this novel - Orlando's transformation, and the way s/he barely ages over the centuries (this extends (though to a lesser degree) to the people around her,) - but this is likely to put some people off.
There's also a dab of casual racism - acceptable in 1928, uncomfortable at best in 2016. It's not a huge amount - but it's there.
Occasionally Woolf just tries too damn hard, and ends up coming off as pretentious. This is rare, but annoying when it happens.