The idea of the journo-coder, programmer-journalist, hacker-journalist, journo-programmer (the terminology is undecided) is gaining ground as data journalism develops both in Britain and internationally. Programmers are coming into newsrooms, journalists are venturing further into programming and there is some blurring where the two meet. Data journalism (DJ) is certainly becoming the Big Buzz Story in the media but so far little has been written about it. This new, jargon-free text, edited by John Mair and Richard Lance Keeble (with Teodora Beleaga and Paul Bradshaw), provides an original and thought-provoking insight into DJ. The first section, with contributions from Teodora Beleaga and Simon Rogers. explores various definitions of DJ; in another, experts, such as Paul Bradshaw, Nicola Hughes, Daniel Ionescu and Pupul Chatterjee provide some useful tips on developing DJ skills. • Tom Felle interviews a group of international data journalists and finds they all argue their work can play a crucial democratic role in holding the powerful to account • Andy Dickinson wonders if the growing field of sensor journalism offers an insight into what comes next for DJ • Jacqui Taylor, Bella Hurrell and John Walton focus on data visualisations • Ændrew Rininsland argues that anyone willing to learn D3 will find they are given an unparalleled ability to create visualisations that bring data alive • Arthur Lashmar shows how an international consortium of journalists used DJ skills to expose the use of offshore tax havens by the worlds rich and famous Other chapters are provided by Chris Frost, Liz Hannaford, Jonathan Hewett, Gabriel Keeble-Gagnère, Damian Radcliffe, Yaneng Feng, Qian Li and John Burn-Murdoch.