How did letters construct and sustain various types of communities in the ancient Mediterranean? The volume under review, a revised collection of papers presented at a 2011 conference at Durham University, contributes to scholarly understanding of a long-neglected dimension of ancient letters: the inherently “prosocial” character of ancient epistolography. According to the editors, three main qualities contributed to the “community-building” character of ancient letters: the letter’s permanence, its ability to extend social interaction beyond those who are present across space and time, and its protean generic ideology. As written texts, the letter as verbal artefact was a site of communion, memory, and authority that could enjoy countless lives in the (intended or unintended) broadcast of letter content in conversation and writing, oral presentations, private re-readings, and subsequent preservation. The letter contributed to the social cohesion and communal identities of trans-Mediterranean political, religious, and philosophical communities in unique ways while also complementing oral communication and other forms of communication (e.g., the decree). Furthermore, the ideological flexibility of ancient letters (here termed loosely as a “genre”; cf. p. 13) furnished diverse strategies for authorial self-fashioning and persuasion. In this way, the essays in the volume emphasize the “soft” power of letters to exert influence without force and to project specific moral or civic values which may also define and, in a sense, immortalize one’s self and community for moments of transhistorical friendship among like-minded literati initiates.