The High Frontier by Gerard K. O'Neill, a book advocating space colonies, is free as a Kindle book this week. (If you don't own a Kindle, you can download a Kindle app for whatever device you do use.)
As for why some of y'all might be interested, I will allow Eric Wagner to explain, from an entry from his An Insider's Guide to Robert Anton Wilson (still in print!).
O'Neill, Gerard (1927-1992). A scientist who suggested that planetside civilization didn't seem like the ideal location for a post-industrial, information-age society. He suggested instead self-supporting space colonies. Both Wilson and Leary have enthusiastically supported this idea. Wilson includes such colonies in Schroedinger's Cat.