Tao Teh Ching Chapter 1

Chapter 1
道可道，非常道。名可名，非常名。无名天地之始；有名万物之母。故常无欲以观其妙；常有欲以观其徼。此两者，同出而异名，同谓之玄。玄之又玄，众妙之门。
The Tao(Way) that can be followed is not the eternal Tao (Way), the name that has a name is not the eternal name. Without a name the heaven and earth was born, the name goes on and become the mother of all things. Therefore, without the desire to know, one knows the essential secret of existence; One is bound to know superficial manifestations of the existence when desire is envolved.
These two things, having different names, comes from the same source. The point of which these two are one is called the mystery. When the mystery is pursued step by step (to the top), we reach the gate of all mysteries.

Detailed Comment
This is a very famous but rather simple chapter. It summarized the Tao and give the definition.
道可道，非常道。道, can be translated as way, path, rule, it has so much meaning in it that not a single English word can cover, therefore it is common to leave it as Tao. The second 道 is a verb, i.e., an action. The action of treading a path is translated to Follow.
名可名，非常名。The second 名 is also a verb, it means to define, to give a name to an object or entity.
无名天地之始；有名万物之母。There is an uncanny similarity here between the Tao and Buddhism. The void which does not have a name created the world.
故常无欲以观其妙；常有欲以观其徼。I am not sure how this conclusion was made. However this is perhaps the center of Lao Tzu's teaching. Again, it shares common grounds with other eastern philosophy and religions. When the desire of achieving something is there, the eternal way can never be found. 其 here means "its", I translate it as "existence", this "it" represents Tao.
此两者，同出而异名，同谓之玄。Why With and Without desire come from the same source? They have to, because everything come from the Tao, the point where it separates is the gate of the Tao.
玄之又玄，众妙之门。There are many levels in finding the Tao. To reach the gate, all these levels are to be passed.