7. Carl Sagan
The scientific community —particularly the space community—lost a huge ally in 1996 when acclaimed scientist Carl Sagan passed away.
The preeminent scholar on extraterrestrial life, he was also an author, with his work Cosmos securing the spot for best-selling science book published in English.
For more information on Carl Sagan and his view on marijuana, see our previous article “Carl Sagan and Pot.”