My personal feeling is that everyone should watch the movie, The True Cost (it's amazing)... and it's probably worth watching more than once over time. The books are listed in no particular order. See which ones look most interesting and are available from the local library and read one or two. It's extremely helpful for me to have images and stories pop into my head when I consider my clothing choices. Get ready to be moved. This is important stuff and we can have an impact!
The True Cost
Unravel (15 min.)
Overdressed || Greta Eagan
Where Am I Wearing? || Kelsey Timmerman
Wear No Evil || Elizabeth L. Cline
Naked Fashion || Safia Minney
To Die For: Is Fashion Wearing out the World || Lucy Siegle
Slow Fashion: Aesthetics meet Ethics || Safia Minney
An updated list here.