Triplanetary

by E. E. (Edward Elmer) Smith

"Triplanetary" by E. E. Smith is a science fiction novel first serialized in 1934 and later expanded as a book in 1948. Ancient alien races wage a cosmic war through human history, secretly breeding two genetic lines across millennia to create the ultimate weapon. When interplanetary commerce falls under pirate attack and mysterious amphibious Nevians arrive seeking iron, Triplanetary agent Conway Costigan must navigate battles between multiple forces while humanity discovers faster-than-light travel and faces its first interstellar conflict.