The King of Sets
Ganesh or Ganapati (translated as the King of sets) is the elephant headed son of Lord Shiva and is widely worshipped by the Hindus. He is the God of the Beginning (so much so that to Ganesh is to begin in many Indian languages), the God of elimination of troubles, and a deity who is easily pleased (with good food).
Ganapati is considered god of wisdom in mythology. Though name "Ganapati" appears in Rigveda, he is not the same God who is worshipped as elephant-headed God today. "Gana" represents a clan and "Pati" is considered chieftain. In Vedic times, image worship did not exist and "Ganapati" stood for Brihaspati or Brahmin. The concept of Ganapati as elephant-headed God evolved in later age. In Hindu mythologies, every deity has a animal vehicle of his own and Lord Ganesh has mouse as his vehicle!
The elephant in Indian ethos occupies significant place. Due to its enormous strength, huge form, sharp memory an cleverness, Indians who visualize divinity in all living creatures naturally ascribe super qualities in this great animal. In our vast tropical forests, roaming elephant herds are led by powerful youthful elephant who commands respect for young and old ones. Among early Aryans and native tribes, elephants evoked fear and respect and it did not take long to conceptualize elephant God who was full of contrasts. For a heavy god, with enormous body and appetite, he rides a small mouse! He has big ears, and small eyes. For his super intellect and sharp memory, he is humble and serves as a scribe to great Vyasa who wrote (dictated) the Mahabharata. He is considered Ameya (beyond measure), and Aprameya (beyond visualization (riddles)). It is perhaps only to represent omniscience form of Almighty that Ganesh is worshipped.