The Psychology of Time Travel by Kate Mascarenhas
Four women invented time travel in 1967. Three went on to become rich and famous. One went on to have a breakdown and be cut off from her friends. The Psychology of Time Travel is clearly science fiction, but it's also a murder mystery and even more about women and their relationships.
I'm in general not a big time travel fan. It can so easily turn wonky. Here time travel is treated almost cavalierly. It was invented and people exploit it. Time travelers themselves regularly get together with their "green selves" and "silver selves," sometimes having over a dozen of themselves in the same place at the same time. It does allow for some interesting interactions and to see how time travel affects the individuals. Because that's what the book is about, how time travel affects people, mentally and emotionally, not about how it works or how it affects cultures or politics.
The murder mystery bit was interesting. It's a locked...