We live in an increasingly digital and globalized world that offers great opportunities for information sharing and the generation of new knowledge. This reality has enabled us to move forward rapidly as a society in many respects, but has also led us to complex, diverse, and interdisciplinary challenges that affect all areas of knowledge such as health, demographic change, and wellbeing; food security and bioeconomy; secure and clean energy; smart and green energy; and climate action and environment - to name just a few that are emphasized by the European Union.

In order to meet these major challenges, we need to build a society that enhances the development of 21^st-century skills in lifelong learning. These skills encompass not only technical and domain-specific abilities, but also domain-independent meta-skills such as the 4Cs: critical thinking, creativity, communication, and collaboration, all needed to manage the complexity of future problems.

On the other hand, dealing with the complexity and uncertainty of tomorrow's problems requires citizens capable of developing their knowledge throughout their lives. In this context, technology can play a key role in generating new learning environments that support learners across both formal and informal learning contexts, facilitating them in developing and practicing 21^st-century skills to face the challenges of the future.

This year, the European Conference on Technology-Enhanced Learning (EC-TEL) aims at engaging researchers, practitioners, educational developers, entrepreneurs, and policy makers in a joint discussion on how to put science, technology, and practice at the service of learning to embrace these challenges on the topic "Lifelong technology enhanced learning: Dealing with the complexity of 21^st-century challenges".

We are looking forward to contributions to feed the debate around this topic on many levels; to discuss and demonstrate how both lifelong learning and technology are indeed a solution to deal with future uncertainty and 21^st-century challenges.

We also encourage participants to extend the debate around the role of and challenges for cutting-edge 21^st-century technologies and advances such as artificial intelligence and robots, augmented reality, and ubiquitous computing technologies for learning. We welcome papers reflecting on practices and different pedagogical approaches, types of learning settings, and application domains that can benefit from such technologies.

Theoretical and conceptual papers, as well as small-scale and large-scale empirical studies are welcome. Moreover, we encourage participants to conduct their scientific inquiry using emerging best practices from open science detailed in this call for papers.

The venue for this year’s conference is Leeds, a vibrant, modern city and an important academic and economic centre. Leeds attracts visitors for its world-class culture, heritage, arts, shopping, food and drink, as well as beautiful countryside and a lively nightlife. Highlights include the Yorkshire Dales, Yorkshire Sculpture Triangle, Royal Armouries Museum, and the World Heritage Site of Saltaire.

The University of Leeds will be hosting both EC-TEL 2018 (03-06 September) and Medical Education Informatics (06-07 September), and we anticipate a lively exchange between the two co-located conferences, based on shared research and practice interests. To support this, EC-TEL 2018 includes a TEL in Healthcare Education stream within the conference itself.