Essential German grammar (Teach Yourself)
Jenny Russ (2010)
A useful reference and workbook for beginner and intermediate level learners who would like to study grammar within the context of communicative topics such as greetings and introductions, likes and dislikes, describing people, making requests.
Grammar rules are explained and demonstrated concisely, before learners then test their understanding by doing three or four exercises, for which answers are provided at the back of the book.
In English and German.
GE GRAM 20 Open access