The introduction of electronic journals into Consejo Superior de Investigaciones Científicas' (CSIC's) collections has been gradual and constant. As the collections have been stable since 2002, the data which has been obtained from analysis of their use in the period 2002-2003 can be looked upon as giving a meaningful picture of developments during these years. The process for establishing the digital collection has been set out in our earlier paper.1 Even though the objectives of this process were clear, it was also evident that it was necessary to count on the backing of the researchers as well as the financial and political authorities of the CSIC. As with any new initiative, it was crucial to undertake trials through which levels of usage could be evaluated and investment justified.

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