Anything by Robert Heinlein. Also We Were Soldiers, by Joe Galloway
started reading Heinlein from 11, great choice.
More a social psycholgist than a sci-fi writer with a vast immagniation
The Discourses- Epectitus
Ape & Essence.
"The Science of Mind," by Ernest Holmes
There literally 100s of 1000s but avoid anything with the following words, phrasing or their derivation in the title, 'vampire, werewolf, bible and alien conspiracies'.
The Man Who Mistook His Wife for a Hat
Not sure if it will broaden the mind, but is certainly an interesting and exceptionally well written book, House Of Leaves by Mark Z Danielowski