Can anyone help me in building my library of 'believable', Earthman at the centre of the story, non-pure science fantasy books. More science fact than fantasy but fictional. For example, have read the most basic type fulfilling my requirements e.g. Ben Bovas Mars & Return to Mars (very good reads), to the middle of the spectrum e.g. Arthur C. Clarkes brilliant quartet Rendezvous with Rama, Rama 2, The Garden of Rama and Rama revealed (brilliant) to possible the far end of the spectrum John Varleys Titan, Wizard and Demon (good but a bit far fetched and fantastical). Any help appreciated.