Link: Denisovans

[New DNA analysis shows ancient humans interbred with Denisovans](http://www.nature.com/news/new-dna-analysis-shows-ancient-humans-interbred-with-denisovans-1.11331). I was unaware that my knowledge of human evolution had fallen so far behind. What we know about early hominids has exploded in the last decade. Can anyone out there recommend a good book that can catch me up?