These best practice guidelines present the type and level of detail required for describing and evaluating the ecological baseline of an environmental assessment. These assessments are vital in determining whether or not there are issues of ecological importance for a site or proposed development and are an essential component of the environment impact assessment process.The guidelines, comissioned by the Institute of Environmental Assessment and compiled by a Working Party comprising representatives from local authorities, non-Governmental organisations, universities, consultants, statutory agencies and developers will provide essential guidance for all parties involved in the planning process. Presented in an attractive and easily accessible way, complete with checklists, summaries and highly illustrated in colour with photographs, maps and diagrams throughout, they explain the importance of consulting and scoping, outline some of the general issues that should be considered in planning and undertaking detailed ecological studies, are one of the first comprehensive guidelines on baseline ecological assessment in the UK, provide clear advice for project managers and clients about the role of ecology in environmental assessment, to help set appropriate briefs and budgets, comprise a comprehensive source of references and survey methods for different ecological groups, and will guide the competent authority in assessing environmental assessments.