This book draws on the disciplines of law, philosophy, and psychiatry to interrogate whether the Mental Capacity Act 2005 meets the challenges posed by mental disorder to decision-making. It is often assumed that to allow space for individuality, any test for capacity must focus only on decision-making processes and not on the substance of the values that underpin decisions. Auckland challenges this assumption, arguing that the current law allows for judgments to be made about the nature of a person's values, without proper scrutiny. This book provides an in-depth analysis of when and how a person's disordered values should be relevant to the determination of their capacity, offering novel suggestions for reforming the capacity test to better reflect the impact of disorder on decision-making. In exploring the implications of this analysis, Auckland concludes that reforms are urgently needed to strengthen the Mental Capacity Act in this respect.