Innovation systems research has long examined how markets and institutions shape innovation across different contexts. Yet this 'top-down' lens often overlooks the view from within: the firms and support organisations whose everyday strategies drive change. This book places these actors and their agency at the centre. Drawing on in-depth case studies of multinational enterprises and technology parks in Mexico and Brazil, it reveals how efforts to build capabilities, forge linkages, and adapt to constraints transform the wider system. Tracing the path from individual action to systemic change, it offers a fresh framework for understanding innovation in developing and middle-income contexts and beyond. Blending theory with grounded evidence, it provides clear insights for students, researchers, and practitioners in innovation management and policy.