The Big Time & No Great Magic

"The Big Time" is Hugo Award winning short science fiction novel by Fritz Leiber. The storyline features members of one of two factions, both capable of time travel, engaged in a long-term conflict called "The Change War". The two opposing groups are nicknamed the Spiders and the Snakes after their respective sponsors. The true forms or identities of the Spiders and the Snakes, how those nicknames were chosen, or whether they are in any way descriptive are all unknown.

"No Great Magic" is the sequel to "The Big Time". The story involves two warring factions that battle by using time travel to change the outcome of events throughout history.