Particle physics tries to describe the forces of nature – that's the way that those particles talk to each other. There are four fundamental forces. There is gravity and the other three forces that work in the sub-atomic world: electromagnetism – fridge magnets and electricity; there is weak force which allows the sun to shine and is responsible for radioactive beta- decay; and there is the stronger nuclear force that sticks the nucleus together called "gluons".
Particle physics is the study or the search for the ultimate building blocks of the universe and, in a sense, I feel the wheels are starting to come off our picture of reality. This is why the Large Hadron Collider is being built.
You should be happy with that, or go to Perkin's "Introduction to High Energy Physics" text if you're not satisfied! :)