E-mails are, rightly or wrongly, a staple of the information and communication technology for managing work and collaborative activities. This paper examines the value of the content of e-mail at a project level rather than at the often-studied level of the individual user. The dataset consists of e-mails authored by an engineering team associated with a large, complex, long term, systems integration project, typical of the aerospace, marine, and defense sectors. The research applied a qualitative content analysis methodology to classify the content (what the e-mail contains) and purpose (why the e-mail was sent) of the e-mail in the dataset. The results of the content analysis were compared and contrasted with secondary evidence from interviews and project documentation to enable a time-phased analysis. The findings show that classifying e-mail content by the categories of management, information, and problem-solving transactions revealed signatures that align with project phases and, more importantly, problems encountered. Finally, we found that the purpose of e-mail is not necessarily consistent with the designated job role or responsibility of the sender or recipient. This paper contributes to empirical data on the relation between communication and project performance and the changing nature of e-mail communication throughout the lifecycle of a project. The findings point to a new way to leverage e-mail content to “manage by e-mail”.