Each year, plaNext aims to publish two volumes; one of which presents a collection of original works following an open call, and the other presents a selection of articles from the annual conference of AESOP Young Academics (YA). plaNext also publishes special volumes following global challenges. This volume includes manuscripts presented at the 15th AESOP-YA Conference “‘Governing the Unknown: Adaptive Spatial Planning in the Age of Uncertainty”, Tirana, Albania, March 29 - 2 April 2021. The call for papers attracted forty original papers. The editors of this volume however invited ten manuscripts, following the nomination made by the chairs of sessions. Due to the ongoing Covid-19 pandemic and its dramatic impacts on all walks of life only six contributors were able to complete and submit their top-quality manuscripts. Their contributions explore a range of complex matters that challenge but also inspire the “governing of uncertainties”, reflecting on topical debates in academia and planning practice. Their contributions explored new planning ideas and technologies that can be further developed to facilitate a sustainable transition towards (more) adaptive planning. The authors’ contributions went through a rigorous peer-review process managed by an editorial board. This board consists of: Prof. Rudina Toto, from Co-PLAN Institute for Habitat Development and key-speaker at the 15^th AESOP-YA conference; Elisa Privitera, from the University of Catania (Italy) who is a member of both plaNext Editorial Board and of the coordination team of YA-AESOP Network (2020-22); Mafalda Madureira from the University of Twente (Netherlands) who is member of plaNext Editorial Board; Pinar Doerder, formerly chair of the YA coordination team; and Kejt Dhrami, who is member of Co-PLAN Institute for Habitat Development and coordinator of planning studies in the Faculty of Urban Planning, Management and Environment at Polis University, she was also one of the local organizer of the AESOP YA conference in Tirana.