Our everyday encounters as members of the public with clerks and assistants in shops and offices are generally experiences as routine, unproblematic events. All competent speakers can cite the standard patterns of dialogue which they belive such encounters typically follow. Nerverthless, public service encounters in real life often present considerable linguistic complexity, revealing culture-specific patterns of organisation and interactive negotiation which are not captured by intuitive accounts. With the aim of identifying such patterns and estabilishing relevant generalisations for second language pedagogy, the PIXI project has analysed corpora of naturally-occurring encounters in bookshops in England and Italy. This volume brings together the data collected in the project, for which over 300 encounters were audio-recorded and transcribed using a modified version of Jefferson’s norms. The corpora are also available in a computer-readable form from the Oxford Text Archive.