I had this book on my TBR list for years. Primarily because of Blade Runner, although I was aware that the latter is not a direct recreation of the book. 
 The story takes place in a PA, dystopia environment. After a nuclear war, most of Earth is either dead, or about to die. Most of the remaining humanity fled the planet, only leaving those who are either not worthy of a space travel or stay to endure the slow decay. New society, new religion, new values frame the life of the population. Deckard is a bounty hunter retiring the biological androids who look exactly like humans, and act very much like humans, but not completely. The story is about life in this society, the value of life. The question whether androids are alive and whole entities etc. 
 I think this is a well written story that dwells into ethical and psychological problems. As such, it's not a hard sci-fi. (Mentioning this for hard sci-fi only fans.) The reason I deducted a star is that sometimes, the character development felt stalled, repetitive or randomized. This is partially just personal taste. I prefer a clearer path (slow or fast, but going somewhere).