Cats who get outside are horrible to try to find, especially if they are in a environment that they aren't familiar with. They don't generally come to their humans even if they are close by. They try their best to stay hidden even when it isn't the best thing for them.
I tried to use my dog to help me find a missing cat once. She wouldn't tell me where he went. I also just recently had a cat go missing. She was in the house and hiding because we had a guest. We tore the house apart looking for her and never did find her. She showed up on her own about 24 hours later. That just shows how cats can melt into their surroundings when they feel the need to hide.
This book shows the process of training a dog to search for cats. She has to be energetic but not too scary. She has to find the cats but not spook them and make them run farther. It is a delicate balance.
You also get to hear about many cases of missing animals. Not all of them have happy endings so beware. I also didn't know that in England dog theft is a big criminal activity to the point where the author's agency doesn't get involved much anymore after all the credible death threats they have received.
This is a quick, easy read for the animal lovers in your life.