Review of the hardback: '… it is a data-driven volume written by experienced Africanists with expertise spanning the continent. … the volume as a whole has the potential to encourage linguists working with apparent genetic units in Africa to consider how areal features contribute to our conceptualisation of 'relatedness' and to re-assess the importance of genetic units in accounting for similarities across languages within a particular geographical area where contact is attested or historically likely.' Journal of Linguistics