Conversation so far:
What were Sven Hedin's political views?
Hedin was a monarchist.
Where was Sven Hedin from?
Sven Hedin was born in Stockholm, Sweden.
What else is interesting about Sven Hedin's political views?
From 1905 onwards he took a stand against the move toward democracy in his Swedish homeland.
Who did Sven Hedin support in World War I?
In World War I he specifically allied himself in his publications with the German monarchy and its conduct of the war.
Why did Sven Hedin start supporting Germany in both World Wars?
Hedin felt that Soviet Russia posed a great threat to the West, which may be part of the reason why he supported Germany during both World Wars.

Question: Did he write any books during this time?
Self-contained rewrite: Did Sven Hedin write any books during this time of World War I?