Today's word is old and you you won't find much older than 'The Heavens'! The book itself is quite old too, it's my lovely old astronomy book from 1866.
I haven't read it yet, it was a birthday gift last year, but I'm sure it'll be an interesting read. The oldest astro-book I've read was one from 1930 and it was really interesting to read that and the science of the time, knowing so much more than they did then about astronomy - that book was written before Pluto was discovered! I'm sure the 1866 book will be even more interesting to read, to see the ideas and scientific thoughts/knowledge of the time.