The recommendation below is an advertisement. Most of the links here are part of Amazon's affiliate program (unless otherwise stated), which helps support this website. It's also more than that - it's a hand-picked recommendation of something I've used myself. If you're interested, here is a full list.
Color and Light by James Gurney
Some of you may remember James Gurney's breathtaking work in the Dinotopia series. This is easily my favourite book on the topic of colour and light, and comes highly recommended by any artist worth their salt. While it speaks from the perspective of a traditional painter, the information in this book is invaluable for work in any medium.