PADev is an innovative toolbox of tools and methods that have been designed to get a bottom-up assessment of development and change in a particular area over a period of time based on the value systems of the population. PADev is thus a holistic and participatory approach to development assessment. It differs from conventional assessment methods which tend to focus on a single agency/project/programme with an expert-driven approach to evaluation. Instead, PADev assesses a wide range of changes, projects and agencies and may look back over 20-30 years. As an alternative approach to conventional assessment it enables the construction of a “big picture” of development and change for an area that can be very useful to both development agencies and local communities. This guidebook has been written specifically for those interested in using the PADev methodology. It offers an introduction to this style of workshop set-up and the nine participatory PADev exercises that can be run over three days. However it is not intended to be prescriptive and encourages experimentation and adaptation as circumstances require.