Surely, you have heard the story of the astronaut coming back

to earth, looking as young and fit as when he left, with

everybody else on earth hardly being able to walk because of

the years added to their age, as a result of the difference in

how time passed on Earth as opposed to the time passing

over the astronaut. Many would argue that this is just an

illusion, when in fact, although not literally true, there is a

scientific explanation for this: indeed, you must have guessed it

by now, Einstein's theory of relativity is perfectly applicable and

it is Einstein's Theory of Relativity we need to resort to in

order to not only explain such hypothetical cases as this one,

but also understand the particularities of the world we live in.

Upon mentioning Einstein and his famous Theory of Relativity,

the first thing that comes to one's mind is the notorious E=mc

2 However, there is more to the theory of relativity than this:

in addition to the implications concerning mass and energy, it

implies further several areas, such as, among others: space,

time, and gravity. We invite you to join us on our journey

through the main points of Einstein's Theory of Relativity. This

booklet is, thus, intended to show beginners to a brief and

explanatory introduction to Einstein's Theory of Relativity –

what it means, how Einstein got to develop it, its ramifications,

as well as its applications and implications to present science

and our lives as we know them.