Gautama Buddha : Fundamentals teachings

A statue of the Buddha from Sarnath, 4th century CE

The Four Noble Truths:
that suffering is an ingrained part of existence;
that the origin of suffering is craving for sensuality, 

acquisition of identity, 

and annihilation; 

that suffering can be ended; 

and that following the Noble Eightfold Path is the means to accomplish this.

The Noble Eightfold Path :
right view,
right intention,
right speech,
right action,
right livelihood,
right effort,
right mindfulness,
and right concentration.

Dependent origination: the mind creates suffering as a natural product of a complex process.

Rejection of the infallibility of accepted scripture:
Teachings should not be accepted unless they are borne out by our experience and are praised by the wise. See the Kalama Sutta for details.

Anicca (Sanskrit: anitya) : That all things that come to be have an end.

Dukkha (Sanskrit: duḥkha) : That nothing which comes to be is ultimately satisfying.

Anattā (Sanskrit: anātman) : That nothing in the realm of experience can really be said to be "I" or "mine".

Nibbāna (Sanskrit: Nirvāna) : It is possible for sentient beings to realize a dimension of awareness which is totally unconstructed and peaceful, and end all suffering due to the mind's interaction with the conditioned world.

http://en.wikipedia.org/wiki/Gautama_Buddha