This special issue of the Requirements Engineering Journal (REJ) contains extended versions of selected papers from the 22nd IEEE International Requirements Engineering Conference (RE’14). This continues a long-standing collaboration between RE and REJ to invite the authors of the best papers presented at the conference to submit extended papers to reach the wider journal readership. As program chair of RE’14, it is my pleasure to introduce these papers to you. The conference was held at the Blekinge Institute of Technology in Karlskrona, Sweden, August 25–29, 2014, with Tony Gorschek as general chair, Sarah Gregory and Marjo Kauppinen as industry co-chairs, and Juergen Borstler as organizing chair. Three hundred people registered for the main conference, and over 420 registered in total for the conference and its associated tutorials, doctoral symposium, and workshops. The conference featured stirring keynotes by Anthony Wasserman, Annie Anton, and Anthony Finkelstein. RE’14 also offered a variety of panels, mini-tutorials, lightning-round poster and tool demonstrations, an Industry Lab, and multiple social activities to foster new ideas, uses, and collaborations in requirements engineering. The theme of RE’14 was innovation. Innovation in requirements engineering explores new ideas and breakthroughs in the area. Innovation through requirements engineering describes how its practices, processes, models, methods, and frameworks enable and support innovation in product development. RE’14 received 115 submissions to its research track by authors from 30 countries. Following review by three members of the program committee and an online discussion among the reviewers of each paper, the program board met and used the reviews and discussion to select 31 research papers for presentation at the conference, an acceptance rate of 27 %. I extend my thanks to the program committee and the program board for their service, and to the authors for their submissions. The high quality of the authors’ papers provided the strong technical program for RE’14, and that is reflected in the papers offered here. The three papers published in this issue are extended versions of the work invited from the best of those RE’14 research-track papers. Each of these extended papers underwent rigorous, additional review by three reviewers in accordance with the REJ review process before acceptance to the special issue. The first paper is ‘‘TiQi: Answering Unstructured Natural Language Trace Queries’’ by Piotr Pruski, Sugandha Lohar, William Goss, Alexander Rasin, and Jane ClelandHuang. Developers often find it hard to specify complex trace queries, which limits their access to the traceability information they need. In response to this problem, the authors have developed TiQi, a process to automatically translate unstructured spoken or written natural language queries into executable SQL (structured query language) statements. TiQi is supported by a database query mechanism as well as by domainand project-specific elements. Experimental results show that users prefer written natural language queries over spoken queries. In experiments on two datasets, TiQi’s accuracy rate in translating queries is shown to vary from 47 up to 93 %. Two additional experiments evaluated the performance of TiQi’s ambiguity resolution and what the sample size of the trace query collection needs to be to construct a & Robyn R. Lutz rlutz@iastate.edu