This chapter explores the immigration law and investigates how and under what conditions immigration law is applied to individual cases. The exploration of the process of implementing immigration law thus yields very different results to what an analysis of the implementation outcomes would deliver. In order to prove that she/he fulfils the criteria of residence, an applicant does not only have to provide proof through documentary evidence, but also copies of that evidence for the files in the immigration office. However, immigration law is not a mere set of technical guidelines, but a political instrument. While it can be very difficult to compare individual cases, in general, there was a wide congruence in the decisions made by the immigration offices. Looking beyond decisions, it is evident that the processes of reaching a decision, but also ways of case-handling and institutional self-presentation, differ even more greatly both between and within immigration offices.