You can legally download old German grammar books (e.g., A German Grammar for Schools and Colleges by W. H. Van der Smissen, 1907) from or Project Gutenberg . However, these are outdated for modern speaking exams but useful for grammar nerds.

If you are self-studying (not in a classroom), the textbook alone can be tricky. Here is a recommended workflow:

Aspekte neu B1 plus - Digital Edition allango - Klett International

Despite the above, you might still find websites offering Aspekte Neu B1 PDF or other textbooks for "free." Before you click, consider these facts: