In a post-nuclear war Earth where most animal life is extinct and humanity emigrates to Mars with android servants, bounty hunter Rick Deckard is tasked with 'retiring' a group of the most sophisticated androids yet built—ones that may be nearly indistinguishable from humans. The novel interweaves questions of empathy, authenticity, and what makes a being worthy of moral consideration. The source novel for the film Blade Runner, richer in philosophical texture than its adaptation.