If you stuck to conventions you should be able to do $this->Form->input('category_id') and it will just work (with passing $categories to the view). Cake does use the key of the array for the value in the select so you must be passing the wrong data.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.