Don's work is primarily concerned with management of resources and conservation. On the technical side, he tries to correct simple assumptions and models that typically underestimate risks and foster complacency about human impact. Don is also grappling with underlying attitudes and motivations that have produced disastrous results in management of resources. These are partially economic and social issues, but he thinks that technical difficulties are also a factor. This is especially true when substantial uncertainties are present, but decisions must be made. The economic literature on renewable and non-renewable resources would benefit more from attention to data, proper methods of inference and dealing with uncertainty. A recent paper with Walters and Hilborn led to an intense scientific discussion that was noted in a feature NY Times article.