Digital library appALTER the reader, which can run ALTER textbook publishing on tablets. App-textbooks correspond to the extent and structure of printed titles. Selected titles also contain interactive elements. App-textbooks are suitable for school teaching and pupils' homework. Application features:  - Intuitive user-friendly operation  - Easy orientation in a publication  - Easy browsing and active content  - Zooming  - Remembering your reading chapters / pages Further functions for selected films:  - Supplementing omissions from the menu  - Correspondence responses  - Evaluating the correctness of the solution (feedback)  - The repair of wrong solutions  - Songs and spoken texts  - Image and text attachments Library appALTER:  - Download publications available from the server  - Sorting books by keywords  - My Books