Janice chose the last book she wanted to borrow from the library shelves and sat in the corner in her favorite chair. The librarian, Richard, looked over at her and smiled.

She returned the smile and began to read Advanced Mathematics. Janice wasn't studying, she had graduated from university years ago, but she still liked reading text books. She had no time fiction and fantasy nonsense.

After reading for an hour. Janice rubbed her eyes, placed her bookmark inside, left her seat and went for a glass of water. When she returned, she noticed the bookmark had been moved to a different page. Not only that, but the book she had been reading was different too!

Searching among her other books and even in her bag, she couldn't find the book she left on the table!

She went over to Richard, carrying the other book and asked if anyone had gone over to her place where she was sitting?

"No, we are quiet for a week day. What book were you reading?" He enquired.

"Advanced Mathematics by..." She began to say.

"Like that one." Richard pointed to the book under Janice's arm.

She looked at the book. "Why! Yes! But I could have..."

Richard...