This paper reviews the strengths and weaknesses of the methods used to estimate the incomes of people whose livelihoods depend of the forests. This is the key to understanding their well being and the use of the forest. The authors summarise the methodologies used in 10 case studies and use these cases, as well as insights from their own research in Indonesia, to suggest ways of overcoming the logistics of collecting income information related to possibly hundreds of products. This review indicates some of the reasons why good information remains unavailable: expense of collecting information, weak application of methods and incomparable data.