This is the 1178th most frequent German word.
handeln
"Handeln" means "to act, trade, or deal."
In this sentence, 'handeln' is used to mean 'to act' or 'to take action', conveying the need for immediate intervention.
Wir müssen jetzt schnell handeln, um das Problem zu lösen.
We must act quickly now to solve the problem.
Here, 'handeln' means 'to be about' or 'to deal with a topic', indicating what the subject matter of the book is.
Das Buch handelt von der Geschichte eines mutigen Kämpfers.
The book is about the story of a brave fighter.
In this context, 'handeln' refers to 'to trade' or 'to negotiate', emphasizing the act of offering or bargaining.