This is an answer to the question my faithful friend Jackie asked in her comment to Backstage:
"Are you able to write ANYTHING?! I mean, as long as you get the documents and details, would you be able to write about any topic/issue/subject even if it's about - let's say - cell biology, automation engineering or computer science? Is it only that those people just need someone who writes the TEXT itself without really having knowledge of the stuff they have to write or do you need to actually understand that stuff? (Well at least in my imagination I think that I would need to understand it....)"
Yes, of course I have to understand what I write about, otherwise the result would surely become an utter disgrace for me and, worse, my client. And of course there are many topics I could not write about, without putting in a lot of time and effort for reading, learning and understanding in the first place. Automation engineering and computer science are among them; cell biology isn't, because I actually studied biology at university.
Whatever subject I tackle, I need to feel comfortable with it first. So I usually spend some time with research and reading before I start on a project. Maybe there are subjects (like computer science) where I would have to invest so much time and effort in learning about them, that I could not make a profit from them anymore, so I would have to refuse them for practical reasons. But theoretically (although this sounds terribly arrogant), yes, I could write anything - given enough time for research and preparation.
You see, I love to learn and to be challenged. I love my job because of the diversity of subjects I read, research and work about. In my 16 years of experience I have already written or made documentaries about quite a variety of topics. Documentaries usually include some travelling and many of them gave me access to unusual places. I have been to arctic islands, primeval forests and archeological digs, inside steel works and power houses, government departments, psychiatric wards and university labs, at factories, farms and feature film shoots, on glaciers and mountaintops and on fishing trawlers.
I have written about a lot of subjects including energy policy, quantum physics, bollywood films, waste disposal, earthquakes, allergies, migratory birds, climate change, compulsive gambling, immigrants, genetic engineering, pedagogics and education, and many kinds of environmental and natural history subjects, often with a focus on fascinating animals like whales and polar bears.
That is why I think there is no limit to possible subjects.
On the downside: My friends refuse to play quiz games or scrabble with me anymore. I have won too often.