The Left Hand of Darkness

I've read Le Guin before and love her stuff. This one is a standout for the multi-dimensional themes she explores.

A far future human visits a planet where the people are ambigendered, and being both (and interchangeably) male and female, reproduction means that either one of a couple can become pregnant each time. Added to the mix are the two main countries where one is a monarchy with a paranoid king and psychopath regent and the other is a totalitarian bureaucracy where various factions fight for power. Le Guin explores a slew of binary issues, political intrigue, sexuality and social relationships, religious enlightenment vs taoist philosophy, and what does 'alien' mean?