A review is given of major progress towards addressing unsolved fundamental puzzles about the Sun. The solar magnetic field is generated by dynamo action in the solar interior. Several mechanisms may heat the corona to 106 K and drive the solar wind. Occasionally, giant flux ropes (prominences) erupt and produce huge CMEs and solar flares. A new theory is presented for the origin of the twist observed in erupting prominences and the nature of reconnection in the rise phase of a flare or CME.