Guillermo is a biologist trained at the University of Oxford and a retired professor specialising in conservation and management of biological diversity. He served as Venezuela’s minister of people’s power for ecosocialism and waters (2015–2016) and has held positions such as president of the National Science Foundation, deputy minister of science and technology, president of the International Centre for Decolonisation Studies, and coordinator of education at the Simón Bolívar Institute. He also served as the co-organiser of the Decolonial School of Caracas and the International Seminar on Reparations for Slavery and Colonisation. His areas of interest and research include reparations for slavery and colonisation, the environmental question, ecosocialism, and civilisational crisis.