Introduction : agroecology as a transdisciplinary, participatory and action-oriented approach / V. Ernesto Méndez, Christopher M. Bacon, and Roseann Cohen -- Agroecology : roots of resistance to industrialized food systems / Stephen R. Gliessman -- Transformative agroecology : foundations in agricultural practice, agrarian social thought, and sociological theory / Graham Woodgate and Eduardo Sevilla Guzmán -- Political agroecology : an essential tool to promote agrarian sustainability / Maneul González de Molina -- Learning agroecology through involvement and reflection / Charles Francis, Edvin Østergaard, Anna Marie Nicolaysen, Geir Lieblein, Tor Arvid Breland, and Suzanne Morse -- Complexity in tradition and science : intersecting theoretical frameworks in agroecological research / John Vandermeer and Ivette Perfecto -- Agroecology, food sovereignty, and the new green revolution / Eric Holt-Giménez and Migeul A. Altieri -- The intercultural origin of agroecology : contributions from Mexico / Francisco J. Rosado-May -- Participatory action research for an agroecological transition in Spain : building local organic food networks / Gloria I. Guzmán, Daniel López, Lara Román, and Antonio M. Alonso -- Agroecology, food sovereignty, and urban agriculture in the United States / Margarita Fernandex, V. Ernesto Méndez, Teresa Mares, and Rachel Schattman -- On the ground : putting agroecology to work through applied research and extension in Vermont / Debra Heleba, Vern Grubinger, and Heather Darby -- Agroecology as a food security and sovereignty strategy in coffee-growing communities : opportunities and challenges in San Ramon, Nicaragua / Heather Putname, Roseann Cohen, and Roberta M. Jaffe -- The Mesoamerican agroenvironmental program : critical lessons learned from an integrated approach to achieve sustainable land management / Isable A. Gutiérrez-Montes and Felicia Ramírez Aguero -- Analysis of tropical homegardens through an agroecology and anthropological ecology perspective / Alba González-Jácome.