I picked up my first Paolo Coehlo book at the airport in Paris on my way home from Israel last month. My daughter had bought two of his books to take on our trip to Israel and loved them.
The Zahir, Paolo explains, means "'visible' present; incapable of going unnotice.' it can refer to an object or a person, and that object or person gradually takes over our every thought until we are unable to think of anything else. this could be considered a state of holiness or a state of madness."
This also means that the focus on 'something that gradually takes over our every thought' can cause us a lot of grief and suffering. For some people it may be income, others it may be the elusive romantic relationship of their dreams, fear for the safety of loved ones, looking for inner peace or may be avoiding all the people in their lives that are difficult.
For me my zahir can be my weight loss goal. You may want to notice where you are so focussed on an outcome or a wish that it is negatively impacting your quality of life.