The chapters in this volume take different approaches to the exploration of language acquisition processes in various populations (monolingual and bilingual first language acquisition, L2 acquisition) and address issues in syntax, morphology, pragmatics, language processing and interface phenomena. This volume is a tribute to Juana M. Liceras' fundamental and enduring contribution to the field of Spanish Second Language Acquisition (SLA). All the chapters in the volume are linked to or inspired by Juana's extensive body of work, and, like Juana's research, they all stand at the crossroads of formal and experimental linguistics. Together, the studies presented in this volume are a reflection of Juana's impact both as a mentor and as a collaborative researcher while at the same time showcasing current trends and new directions in the field of generative SLA.