Or it could be something that simply does not make a good reference. I kept many of my math and computer science text books as references for later. On the ot

Or it could be something that simply does not make a good reference. I kept many of my math and computer science text books as references for later. On the other hand, the political science class I took made us read through many books where reading them once was very enlightening, but I have never felt a desire to refer back to them.