Hi,

I'm sure someone must have already mentioned Jules Verne, so let me introduce you to the lesser known works of a best selling author: Terry Pratchett.

TP is well known as the creator of the Discworld comic fantasy books (which are on my top list of reccommendation for adults) but has also written a few less known children's books, both in the Discworld and unrelated to it.

The Bromeliad trilogy is a a seried of 3 books (Truckers-Diggers-Wings) about the Nomes, a 4 inch tall ET tribe that's shipp wrecked in Earth and forgets about its history.

The books are very fun to read, but also beneficial for children as they discuss allegorically quite deep philosophical questions.

There's plenty more info on the Bromeliad trilogy, as well as TP's other works on wikipedia.

On a side note, TP's not strictly SciFi books such as 'The amazing Maurice and his educated cats' and the 'Wee Free Men' trilogy are also really good books for children and adults alike. Not to mention that the Discworld series is by far the most enjoyable read I've had for years!