The renaissance of corpus linguistics and promising developments in experimental linguistic techniques in recent years have led to a remarkable revival of interest in issues of the empirical base of linguistic theory in general, and the status of different kinds of linguistic evidence in particular. Consensus is growing (a) that even so-called primary data (from introspection as well as authentic language production) are inherently complex performance data only indirectly reflecting the subject of linguistic theory, (b) that for an appropriate foundation of linguistic theories evidence from different sources such as introspective data, corpus data, data from (psycho-)linguistic experiments, historical and diachronic data, typological data, neurolinguistic data and language learning data are not only welcome but also often necessary. It is in particular by contrasting evidence from different sources with respect to particular research questions that we may gain a deeper understanding of the status and quality of the individual types of linguistic evidence on the one hand, and of their mutual relationship and respective weight on the other. The present volume is a collection of (selected) papers presented at the conference on 'Linguistic Evidence' in Tubingen 2004, which was explicitly devoted to the above issues. All of them address these issues in relation to specific linguistic research problems, thereby helping to establish a better understanding of the nature of linguistic evidence in particularly insightful ways.