The central topic for this book is the ethics of treating individuals as though they are members of groups. The book raises many interesting questions, including: Why do we feel so much more strongly about discrimination on certain grounds - e.g. of race and sex - than discrimination on other grounds? Are we right to think that discrimination based on these characteristics is especially invidious? What should we think about `rational discrimination' - `discrimination' which is based on sound statistics? To take just one of dozens of examples from the book. Suppose a landlord turns away a prospective tenant, because this prospective tenant is of a particular ethnicity - arguing that statistics show that one in four of this group have been shown in the past to default on their rent. That seems clearly unfair to people of this ethnicity. But we are routinely being judged in this way - not just on the basis of our ethnicity, but assumptions are made about us and decisions taken about us based on our gender, religion, job, post-code, hobbies, blood-group, nationality, etc. Now suppose that another landlord turns away a convicted criminal, arguing that one in four of convicted criminals have been shown to be unreliable rent payers. Is our intuition the same as before? Should it be? This book is suitable for all students of philosophy, especially those with an interest in applied ethics.