The service matrix V, portrayed as V in Table 3.1, precisely speciﬁes what data are required to describe the world city network. I need: (a) to identify a set of global service ﬁrms; (b) to select a set of cities from within which can be found the cities that make up the world city network; and (c) to ﬁnd or derive service values that show the importance of each city to the service ofﬁce network of each ﬁrm. The argument proceeds in two stages. First, the process of gathering the appropriate information is described. The method employed is described as ‘scavenging’, since any information that can inform the data needs is recorded. Second, the conversion of this multifarious information into comparable data across ﬁrms is described. The data are produced by devising a uniform scale of service value that is then applied separately to the speciﬁc information gathered on each ﬁrm. The end result is a data matrix of the service values of global service ﬁrms across world cities to describe and analyse the world city network as it existed in the year 2000.