Time travel was once considered scientific heresy, and I used to avoid talking about it for fear of being labelled a 'crank.'

Without imperfection, you or I would not exist.

Disorder increases with time because we measure time in the direction in which disorder increases.

However difficult life may seem, there is always something you can do and succeed at.

I am just a child who has never grown up. I still keep asking these 'how' and 'why' questions. Occasionally, I find an answer.

So great a contribution to physics was Two New Sciences that scholars have long maintained that the book anticipated Isaac Newton's laws of motion.

My first popular book, 'A Brief History of Time,' aroused a great deal of interest, but many found it difficult to understand.