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I'm looking for simple but well-known and interesting German literature to improve my reading comprehension as an intermediate learner. It should fulfill the following criteria:
- Well-known: Either classical literature, or contemporary and popular.
- Interesting: Should not be written for young children. Harry Potter passes, Green Eggs and Ham does not.
- Simple: On average, the sentences should not be very long, and most words among the 4000 most common. To quantify, let's say around 70 German Flesch Reading Ease. I took some (too small) random samples and found that Schätzing's Der Schwarm scores 30, while Zweig's Schachnovelle scores 55 and the Harry Potter translation 75.
- „Standard“: Not much deviation from Hochdeutsch, and not much slang.
- Original: Originally written in German. Revisions that make the work conform to neue Rechtschreibung and update archaic words are welcome but not necessary.
Please detail any other properties that make the book useful for learners. One book per answer, please.