If you would like to buy a copy of the book go here https://www.amazon.com/Dark-Tower-I-Gunslinger/dp/1501143514/ref=sr_1_1?ie=UTF8&qid=1516215456&sr=8-1&keywords=the+gunslinger+stephen+king
How about watching the movie https://www.amazon.com/Dark-Tower-Idris-Elba/dp/B074FC83Q4/ref=sr_1_1?ie=UTF8&qid=1516215592&sr=8-1&keywords=the+gunslinger+movie
Interesting websites about the book https://www.stephenking.com/darktower/book/the_dark_tower_i_the_gunslinger_(revised).html
https://www.wired.com/2017/05/dark-tower-trailer/
Movie trailer https://www.youtube.com/watch?v=GjwfqXTebIY