This book is open access under a CC BY license. The volume constitutes the proceedings of the 18th International Conference on Agile Software Development, XP 2017, held in Cologne, Germany, in May 2017. The 14 full and 6 short papers presented in this volume were carefully reviewed and selected from 46 submissions. They were organized in topical sections named: improving agile processes; agile in organization; and safety critical software. In addition, the volume contains 3 doctoral symposium papers (from 4 papers submitted).

This book contains the refereed proceedings of the 14th International Conference on Agile Software Development, XP 2013, held in Vienna, Austria, in June 2013.

In the last decade, the interest in agile and lean software development has been continuously growing. Agile and lean have evolved from a way of working -- restricted in the beginning to a few early adopters -- to the mainstream way of developing software. All this time, the XP conference series has actively promoted agility and widely disseminated research results in this area. XP 2013 successfully continued this tradition.

The 17 full papers accepted for XP 2013 were selected from 52 submissions and are organized in sections on: teaching and learning; development teams; agile practices; experiences and lessons learned; large-scale projects; and architecture and design.

Extreme Programming has come a long way since its ?rst use in the C3 project almost 10 years ago. Agile methods have found their way into the mainstream, and at the end of last year we saw the second edition of Kent Beck s book on Extreme Programming, containing a major refactoring of XP. This year, the 6th International Conference on Extreme Programming and Agile Processes in Software Engineering took place June 18 23 in She?eld. As in the yearsbefore, XP 2005provideda unique forum for industry and academic professionals to discuss their needs and ideas on Extreme Programming and - ile methodologies. These proceedings re?ect the activities during the conference which ranged from presentation of research papers, invited talks, posters and demonstrations, panels and activity sessions, to tutorials and workshops. - cluded are also papers from the Ph.D. and Master s Symposium which provided a forum for young researchers to present their results and to get feedback. Asvariedastheactivities werethe topicsofthe conferencewhichcoveredthe presentationofnewandimprovedpractices, empiricalstudies, experiencereports and case studies, and last but not least the social aspects of agile methods. The papers and the activities went through a rigorous reviewing process. Each paper was reviewed by at least three Program Committee members and wasdiscussedcarefullyamongtheProgramCommittee.Of62paperssubmitted, only 22 were accepted as full papers."

Software development is being revolutionized. The heavy-weight processes of the 1980s and 1990s are being replaced by light-weight, so called agile processes. Agile processes move the focus of software development back to what really matters: running software. This is only made possible by accepting that software developmentisacreativejobdoneby, with, andforindividualhumanbeings.For this reason, agile software development encourages interaction, communication, and fun. This was the focus of the Fifth International Conference on Extreme P- grammingandAgileProcessesinSoftwareEngineeringwhichtookplacebetween June 6 and June 10, 2004 at the conference center in Garmisch-Partenkirchen at the foot of the Bavarian Alps near Munich, Germany. In this way the conference provided a unique forum for industry and academic professionals to discuss their needs and ideas for incorporating Extreme Programming and Agile Metho- logies into their professional life under consideration of the human factor. We celebrated this year's conference by re?ecting on what we had achieved in the last half decade and we also focused on the challenges we will face in the near future.