While the physical book is widely used, various digital versions and supplementary PDFs are available through official and educational channels:
: Don't just read; listen to the integrated audio to catch high-level intonation and "Redemittel" (idiomatic expressions). Sicher C1.2 Pdf
If you want to pass C1, you must have the Arbeitsbuch PDF. The Kursbuch teaches you the what ; the Arbeitsbuch teaches you the how . While the physical book is widely used, various