With an ageing population, the number of people with dementia is expected to increase in the coming decades. Dementia can seriously impair a persons ability to act and decide. In the Netherlands, adults can provide for such a future period of incapacity through a so-called levenstestament. A levenstestament can include the appointment of an attorney for financial, medical and/or personal matters, but also the adults wishes, preferences and instructions regarding these matters. Over the past decade, the levenstestament has become increasingly popular in the Netherlands. A major concern, however, is that the levenstestament becomes active at a time when adults will generally be increasingly unable to supervise the execution of the levenstestament and indicate whether they are satisfied with the actions of their attorney. This book provides a thorough analysis of the current regulation and application of the levenstestament based on legal-normative and empirical research. Based on comparative law research, recommendations have been formulated to improve the regulation of the levenstestament and address problems that arise in practice.