Saliva has antibacterial properties. It also has things called nerve growth factor, skin growth factor, histatins which help with wound closure. So when you see an animal licking a wound or even a mom kissing a child's boo-boo, there's some, there's some good science behind why one might do this.

In 'Packing for Mars,' I tried to convey the importance of getting young people interested in science.

I don't read good books anymore, it seems; I just buy them and put them on the shelf and every now and then walk over and pet them. I'm like the optimistic dieter who fills her closet with clothes two sizes too small and dreams of the day she can wear them. I know just what I want to do when I retire.

To keep your he-man jaw muscles from smashing your precious teeth, the only set you have, the body evolved an automated braking system faster and more sophisticated than anything on a Lexus. The jaw knows its own strength. The faster and more recklessly you close your mouth, the less force the muscles are willing to apply.

I used to do my best thinking while staring out airplane windows. The seat-back video system put a stop to that. Now I sit and watch old' Friends' and 'Everybody Loves Raymond' episodes. Walking is good, but here again, technology has interfered. I like to listen to iTunes while I walk home. I guess I don't think anymore.

Science is you! It's your head, it's your dog, it's your iPhone - it's the world. How do you see that as boring? If it's boring, it's because you're learning it from a textbook.

My books are not really books; they're endless chains of distraction shoved inside a cover. Many of them begin at the search box of Pub Med, an Internet database of medical journal articles.

I don't write on topics that require a lot of urgency. But in 'Stiff,' I wanted to change people's hearts about organ donation. Whenever I get a chance, I try to talk about that.

Pet foods come in a variety of flavors because that's what humans like, and we assume our pets like what we like. We're wrong.

Weightlessness was unbelievable. It's physical euphoria: Nothing about you has any weight. You don't realize that you are weighed down all the time by yourself, and your organs, and your head. Your arms weigh down your shoulders. In space simulation, you get to fly like Superman! You're hanging in the air! It's the coolest thing.

Picking my topics is sort of a process of elimination for me. Most things don't work for me. I like to cover science and unexpected things happening in labs. Also, theoretical research doesn't work for my style. I need scenes and interactions. Then, humor. I'm having the most fun when I can have fun with my work.

Every now and then, someone will tell me that one of my books has made them laugh out loud. I never believe them because: a.) my books don't make me laugh out loud; and b.) sometimes I have said this to a writer, when really what I meant was, 'Your book made me smile appreciatively.'

A lot of people would say 'sexy' is about the body. But to me, 'sexy' is a woman with confidence. I admire women who have very little fear.

Fear is not a good teacher. The lessons of fear are quickly forgotten.

The timing of death, like the ending of a story, gives a changed meaning to what preceded it.

Human beings do not eat nutrients, they eat food.

Jealousy is the fear of comparison.

Technology is the knack of so arranging the world that we don't have to experience it.

Time does not change us. It just unfolds us.

When you say a friend has a sense of humor do you mean that he makes you laugh, or that he can make you laugh?

The more knowledge you have, the greater will be your fear of Allah.

There is greatness in the fear of God, contentment in faith of God, and honour in humility.

If an ignorant person is attracted by the things of the world, that is bad. But if a learned person is thus attracted, it is worse.

Cursed is the man who dies, but the evil done by him survives.

If you expect the blessings of God, be kind to His people.

Do not look down upon any Muslim, for even the most inferior believer is great in the eyes of God.

Solitude is better than the society of evil persons.

Without knowledge action is useless and knowledge without action is futile.

When knowledge is limited - it leads to folly... When knowledge exceeds a certain limit, it leads to exploitation.

Knowledge is the life of the mind.

The greatest truth is honesty, and the greatest falsehood is dishonesty.

Do not follow vain desires; for verily he who prospers is preserved from lust, greed and anger.

O man you are busy working for the world, and the world is busy trying to turn you out.

I have a wish. It as a fear as well - that in my end will be my beginning.

Whenever death may surprise us, let it be welcome if our battle cry has reached even one receptive ear and another hand reaches out to take up our arms.

The true revolutionary is guided by a great feeling of love. It is impossible to think of a genuine revolutionary lacking this quality.

Passion is needed for any great work, and for the revolution, passion and audacity are required in big doses.

Study hard so that you can master technology, which allows us to master nature.

The only passion that guides me is for the truth... I look at everything from this point of view.

Remember that the revolution is what is important, and each one of us, alone, is worth nothing.

I had a project for my life which involved 10 years of wandering, then some years of medical studies and, if any time was left, the great adventure of physics.

Curiosity will conquer fear even more than bravery will.

Chaos is the first condition. Order is the first law. Continuity is the first reflection. Quietude is the first happiness.

If men understood domestic economy half as well as women do, then their political economy and their entire consequent statecraft would not be the futil muddle which it is.

Men come of age at sixty, women at fifteen.

We live in a society bloated with data yet starved for wisdom. We're connected 24/7, yet anxiety, fear, depression and loneliness is at an all-time high. We must course-correct.

I believe that when an elder dies, a library is burned: vast sums of wisdom and knowledge are lost. Throughout the world libraries are ablaze with scant attention.

Turning pro is a mindset. If we are struggling with fear, self-sabotage, procrastination, self-doubt, etc., the problem is, we're thinking like amateurs. Amateurs don't show up. Amateurs crap out. Amateurs let adversity defeat them. The pro thinks differently. He shows up, he does his work, he keeps on truckin', no matter what.

Long-term, we must begin to build our internal strengths. It isn't just skills like computer technology. It's the old-fashioned basics of self-reliance, self-motivation, self-reinforcement, self-discipline, self-command.

As powerful as is our soul's call, so potent are the forces of Resistance arrayed against it. We're not alone if we've been mowed down by Resistance; millions of good men and women have bitten the dust before us.