This is a historical ethnography about age-class formation among the people known as the Imenti and Tigania Meru of central Kenya. By re-examining social anthropology’s long standing study of societies with age-sets or age-­organisation, this research focuses on the problem of historical perspective which such forms of social organisation inevitably provoke. Ethnographers writing in the 1990s, like their counterparts in the 1950s, seemed convinced that the contingent, uncertain, and often ad hoc nature of age-class formation meant that such forms of social organisation were fated to disappear. This thesis aims to overturn such an assumption by presenting differing ethnographic contexts where debate about age-classes’ viability in the present led to community wide reappraisals of traditional and modem categories of thought. By the time of fieldwork in 2001-2003, the formation of Meru age-classes fed into intense debates about what constituted ‘tradition’ and an authentic construction of local social identity. Research in two fieldsites, Imenti and Tigania, allowed for comparison between one segment of the Meru where such organisation is seen as defunct and another section where it is vicariously implicated in local politics. Age-classes, it is argued in the Meru context, are both social formations and tropes within the makings of a local political imaginary. National concerns such as the 2002 General Elections could be locally reinterpreted as power struggles between the generations, such that the transfer of power at the state level was likened to generational succession, a pressing local issue which was still left unresolved when the author left Kenya. Such debates also surfaced in the controversies of differing styles of traditional and modern male circumcision, mirroring a similar debate about clitoridectomy which has come and gone since at least the 1930s. The thesis also examines the uses of Kimeru - the local language - in literacy programmes, where debates and arguments about traditional and modern categories of thought were inscribed within a wider construction of culturally entangled moralities. Examinations of how Meru’s vernacular modernity required a familiar vocabulary to express itself, drawn from tradition, was made through examining forms of popular music.