The PhotoReading book does talk about purpose. Paul offers some suggestions in the book.

I like to think and imagine into the future, What can I see myself doing with this information? How will it help me? Who can I help with this information.? What kind of difference can it make in my life? If it's a subject I've already read about or researched, the purpose usually is along the lines of how will it help my career, my work or life? or WIIFM (what's in it for me? an old one but a good one).

So If I see myself doing something with the information my purpose becomes, I'm learning about x to improve y in my life, to solve y problem or similar. If it could somehow help me I my purpose becomes, I'm reading X so that I can find out if y can be applied to my life so that I can improve that aspect of my life.

Who can I help, Makes it easy to define my purpose. I'm reading this so that I can help *friend* (usually I get an idea how after PhotoReading the book and refine my purpose accordingly.)

For books I don't know if I have a purpose for, which may have been recommended or the title just intrigues me. I PhotoReading with the purpose of finding out WIIFM So that I can decide if I want or need to activate the book later.

You know you've got a purpose when you can add, "so that I can...."

It's not a purpose if it is in the form of a question. The problem with starting using a question as your purpose, you usually have one question and only need one answer, When you have an answer to a question (right or wrong) you're done with the question.

Questions as I just explained should be used to help find your direction.

A purpose is like going into a mall and deciding you want to buy something without a clue what to buy and then start exploring just to see where you can spend your money. You might as well just give it to the first store keeper. Usually people have favourite stores and their purpose is to see if they have anything new for them.

I'm sure there are a few who are Christmas shopping without a clue what to buy. Even so you usually have a purpose, to find a gift for someone you have in mind.

A purpose explains why you are doing something.

In the beginning it takes more time to define our purpose. With experience it becomes natural as reading a novel because you want to know who done it or what happens next. (that's a perfectly acceptable purpose. You can tell because you can finish the statement with "so that I know who done it, so that I know what happened to the hero of the story").

Alex