Think
about the keywords, significant terms, and concepts that describe your
topic.
The terms you use are key to finding books for your topic. You may need to try several terms.
Other terms for phobia might be anxiety or fear
Other terms for art might be painting, drawing, or sculpture
Sometimes your term might be too narrow
For a book about arachnophobia you may need to use phobias
Sometimes your term is too broad
You may need add other words. When you search fear you get hits in the thousands. When you use the phrase "fear of spiders" or arachnophobia, and your topic will be much more manageable.