Advances in network connectivity, power consumption, and physical size create new possibilities for using interactive computing outdoors. However, moving computing outdoors can drastically change the human outdoor experience.  This impact is felt in many kinds of outdoor activities such as citizen science, personal recreation, search and rescue, informal education, and others.  It is also felt across outdoor settings that range from remote wilderness to crowded cities. Understanding these effects can lead to ideas, designs and systems that improve, rather than diminish, outdoor experiences.    This book represents the current results emerging from recent workshops focused on HCI outdoors and held in conjunction with CHI, GROUP, UbiComp, and MobileHCI conferences.  Based on feedback at those workshops, and outreach to other leaders in the field, the chapters collected were crafted to highlight methods and approaches for understandinghow technologies such as handhelds, wearables, and installed standalone devices impact individuals, groups, and even communities.  These findings frame new ways of thinking about HCI outdoors, explore logistical issues associated with moving computing outdoors, and probe new experiences created by involving computing in outdoor pursuits.  Also important are the ways that social media has influenced preparation, experience, and reflection related to outdoor experiences. HCI Outdoors: Theory, Design, Methods and Applications is of interest to HCI researchers, HCI practitioners, and outdoor enthusiasts who want to shape future understanding and current practice related to technology in every kind of outdoor experience.