The two Tocharian languages, A and B, once spoken in Central Asia, still pose many challenges to linguistics. This book delves deeply into interesting phonological, morphological and syntactic issues. Doing this, it arrives at well-founded solutions to a wide range of research problems. The analyses start with events of a shallow time depth, in which only Tocharian A or Tocharian B innovated. The bulk of the book then treats questions of the development from Proto-Indo-European to Tocharian. Plausible solutions are proposed for the dental problem and for salient questions of vocalism. Subsequently, it is argued that in several instances specific syntactic structures can be reconstructed which led to morphological and other structural facts – these investigations lay bare the background of famous problems, such as the gender distinction in the pronoun "I" in Tocharian A, and why the infinitive suffix is attached to a subjunctive stem in Tocharian B. Furthermore, there are important news on dvandva compounds, former diminutives and "verbs of position" in Tocharian. In another investigation, the book demonstrates which Asian language family provided the substratum for Tocharian, profoundly influencing its typological profile. This work is crucial for understanding the two Tocharian languages and for advancing Indo-European linguistics.