This thesis is about the relations between humans and machines, or more precisely, between humans and automation by way of ICTs. Automation can increase both human autonomy as well as human dependence on automation. While automation delegates the rule-based, often routine parts of a complex task to a machine, the most complicated tasks that cannot be automated are left to a human. This thesis is a critical research study of the relations between humans and machines in a sociomaterial perspective in the case of automation of taxes. The tax authorities, the citizens, the automation, the tax rules and regulations, and the online services are seen as entangled in a sociomaterial assemblage. This thesis reports from calls to the tax information call centre, with a focus on the issues experienced by the caller.