In this paper, we examine what the German works of Meister Eckhart (c. 1260-1328) say about heaven, the Kingdom of God and the Kingdom of Heaven. We explain how he understands the presence of the Kingdom of God in us. In a style that is fresh and original, Eckhart says that the Kingdom of Heaven is now already within us. It is in the deepest part of us, in the ground of the soul, but man does not discover it immediately. In the first place, he has to prepare himself and to be receptive to the Kingdom of God, to God within himself. He has to make himself «heavenly», through humility, detachment, equanimity and so on. Furthermore, God «flows» inside this person and He pronounce His Word in him. That is how the human being becomes the son of God, how he receives a «kiss» from God, and how the Kingdom of God breaks through in the ground of the soul. And that finally means participating now in the joy and the blessedness of heaven.