Our research on the language of collective thinking has mainly been undertaken in schools and other educational institutions. Much of the interest, from teachers and researchers, in students working together in the classroom has been motivated by the desire to know if collaborative learning helps individual learning. We can confirm that it does, though only if the conditions are right (Mercer & Littleton 2007; Howe 2010). But that is not the only good reason why it may be useful to get children to work together, and to help them to do so effectively; skills in solving problems collaboratively will be useful to them in the rest of their lives, and not least in the world of work. In Chapter 1 we argued that the emergence of the ability to interthink is likely to have have played a major role in the evolution of our species. Occupations in which we have to plan and solve problems together are as common today as they have ever been. It is widely recognized that having the ability to work well with others is a very desirable attribute in an employee – the advertisements for jobs as varied as accounting assistant, coffee shop manager, IT salesperson and university researcher commonly say something along the lines of ‘candidates should be good at working in a team and possess excellent interpersonal skills’. In this chapter, we will review research on how adults work together in groups to get things done, in actual work situations and in simulated activities, and discuss what this tells us about the characteristics of effective teamwork and the role of talk in the deliberations and interthinking of a team. We will relate the results of that research to our own analyses of talk among groups of students in school, and draw some conclusions.