The plot was that people from the future did extensive research and then made one small change to the past (like moving an object from one side of a room to another) that resulted in a major shift in the future story arc.
In Asimov's The End of Eternity (1955) the timeline-changing Eternals pride themselves on making the Minimum Necessary Change to bring about their desired results. In one example in the book this consists of moving a container from one shelf in a cupboard to another.
Not a full book but a really great short story that has spawned many movies and spin offs.A Sound of Thunder by Ray Bradbury. This short story was published in 1953. I know outside your time frame but a classic staple of all Sci-Fi collections.