> 
> For example, to discover what had caused the war between them, he
>  travelled extensively and questioned many people. He was a **skilful**
>  writer, producing works that are informative and lively.
> 
> 
> 

The answer key to my schoolbook suggests **skilful** as the only possible answer here. However, can't we use **skilled** as well?

(It is a CAE Part 3 task, in which you have to transform a word. In this case, **SKILL**)

The following links introduce us to a pretty similar meaning which I cannot make sense of, to be honest.

<http://www.learnersdictionary.com/qa/the-difference-between-skilled-and-skillful> 

I'd be more than grateful if you let me know about anything obvious that I might be missing here.