What we believe and what we do not believe has a great impact on what we do and fail to do. Hence, if we want to act responsibly, we should believe responsibly. However, do we have the kind of control over our beliefs that such responsibility for our beliefs seems to require? If not, can we maybe influence what we believe by performing actions that make a difference to what we believe? Do we have certain obligations to control or influence our beliefs on particular occasions? And do we sometimes believe responsibly despite violating such obligations, namely because we are excused for violating our obligations with regard to our beliefs? By answering each of these questions, this book provides an account of what it is to believe responsibly