It all started when school teacher Kristen Garrison carried home a bag full of heavy textbooks.

In the information age, I would imagine e-books will become much less expensive than heavy textbooks.

Before he knew it, David was waking up with his heavy textbook of medicine open on his lap.

"We ended up purchasing duplicates of the heavy textbooks so the girls wouldn't have to carry them," he said.

But right now I can only see them working for people on gap years and university students (with lots of big heavy textbooks).

He had grabbed a heavy textbook from the seat and now dropped it onto the accelerator before rolling out the door.

So complicated, in fact, that he fell asleep, the heavy textbook pressing against his abdomen.

Students would not be bent under bulging backpacks filled with heavy textbooks.

He was carrying four heavy textbooks and a sheaf of papers under one arm, and let it all fall to the floor.

Students enjoy working on their tablets and find it convenient not to bring heavy textbooks to school everyday.