Book tours and research provide a lot of travel - too much I sometimes think but we do take vacations.

I'm not an employee who goes to the office every morning at the same time. Then vacations are needed.

We sleep in separate rooms we have dinner apart we take separate vacations - we're doing everything we can to keep our marriage together.

Year by year we are learning that in this restless strenuous American life of ours vacations are essential.

If you want to be an entrepreneur it's not a job it's a lifestyle. It defines you. Forget about vacations about going home at 6 pm - last thing at night you'll send emails first thing in the morning you'll read emails and you'll wake up in the middle of the night. But it's hugely rewarding as you're fulfilling something for yourself.

Over the past 50 years we got versions of X-ray specs and space vacations and even death rays. But the X-ray specs don't fit on your face - they're big things that screen your luggage for guns. Space vacations are real but they cost $20 million. We have death rays but you have to be a triple Ph.D. to play with them.

Now I'm having to live with sales of around 50 000 per album - but I'm pretty content with my place in the general scheme of things even if it's meant I don't drive a fancy car and can't afford grand vacations.

I hate vacations. If you can build buildings why sit on the beach?

Of all the planets apart from Earth in our solar system Mars is the most hospitable. Yeah. Right. Better keep my visit short. And yet despite the discomfort the danger I love it here. I love coming back for these imaginary vacations. The sights are amazing.