|
There is a relatively recent children's book called Tunnels by Roderick Gordon, which has a slightly steampunk vibe, and a much older small children's book called Fattypuffs and Thinifers by Andre Maurois - I mean the book is small, not the children.
Although, I have slightly strayed from the brief as neither of the above are real sci-fi, and they describe hidden civilisations rather than hidden races.
Now, going off on a complete tangent, there is Marrow by Robert Reed which is hard sci-fi (not children's) and does not feature the earth but a hollow planet-like ship. But it is very, very good.
|