The Word Classes of German is a systematic textbook on German grammar aimed at advanced to very advanced learners and teachers of German as a foreign and second language. Concise explanations of the individual word classes and their usage, accompanied by example sentences that illustrate the rules of use, are followed by progressive exercises for internalizing and reinforcing what has been learned. Special attention is given to the contrast with other languages (English, French, Hungarian, Slavic languages). In this way, the textbook can contribute to the training and strengthening of an increased language awareness in the foreign language German. The textbook is particularly aimed at learners who value the ability to speak and write German at the highest level, beyond mere communication skills.