A SIMPLE KEY FOR HENRY RIFLE WITH STAR GAZING AND ASTRONOMY FOR BEGINNERS UNVEILED

The ebook 'Guns, germs and steel' introduced me to The actual fact that the Sahara desert basically isolated Sub-Saharan Africa from the developments elsewhere because the beginning of civilization until European colonialism. My main concern: Is that this real? Had been there major isolated exchanges of information?Is so, where? And why did not it