UFO spacecraft? Harvard's Avi Loeb break down a claim by a former Pentagon official

Best Books on the Search for Alien Life: Astrobiology, SETI, and the Fermi Paradox

The best science books on alien life: Carl Sagan, Avi Loeb, Adam Frank, Lisa Kaltenegger, Arik Kershenbaum, and the Fermi paradox surveys that ask where everybody is.