Foreword: "Since the Convention on Biological Diversity acknowledged the relevance of ?traditional knowledge, innovations and practices of indigenous and local communities” for biodiversity conservation, the past two decades have witnessed a growing acknowledgement of the substantial role that customary law plays in regulating the use of natural resources in many countries. Indigenous peoples? associations have become ever more effective advocates for recognition of customary rights to territory and resources and have increasing influence in international negotiations. The role of customary practices in biodiversity conservation is explicitly acknowledged in the Aichi Targets adopted at the 10 th Conference of the Parties to the Convention on Biological Diversity in October 2010. Target 18 sets the goal that, by 2020, ?the traditional knowledge, innovations and practices of indigenous and local communities, relevant for the conservation and sustainable use of biodiversity, and their customary use of biological resources, are respected, subject to national legislation and relevant international obligations, and fully integrated and reflected in the implementation of the Convention with the full and effective participation of indigenous and local communities, at all relevant l evels.” IUCN?s Regional Environmental Law Programme, Asia, initiated this study ? carried out entirely on a voluntary basis ? in an attempt to better understand the degree to which customary practices and law that govern natural resources are recognized by individual nation States. The study found that more than 60% of the 190 constitutions reviewed provide at least some degree of recognition of customary law, and that only 20% specifically recognize customary law that governs land and natural resources. Some countries that do not provide constitutional recognition of customary law do so by statute. While constitutional recognition was the primary focus of this study, a preliminary compilation of information on statutory recognition of customary law was carried out and is provided as well. This effort benefitted from the input of members of IUCN?s Commission on Environmental Law and Commission on Environmental Economics and Social Policy. We gratefully acknowledge the author, Ms. Katrina Cuskelly, who began this study as a volunteer intern with the IUCN?s Regional Environmental Law Programme, Asia, and continued and completed the work over the course of more than one year. Without her dedication and commitment, this study would not have been possible. We hope that this study provides a basis for continuing research and, eventually, initiatives for constitutional and statutory reform, to appropriately recognize customary law governing natural resources, and to contribute to the security to the people whose lives it governs and who are dependent on the natural resources"