This book explores many of the physical phenamena of the sun. Sun might look an unchanging object in the sky, yet it is far from a simple ball of glowing plasma.In this book the nature of sunspots, CME, Solar Radio Bursts, Solar atmosphere & Surface, Solar interior, Corona, the variety of solar process occurring as different level/height of sun and its atmosphere has been discussed. The influence of these processes on geomagnetosphere has been briefly discussed. This book will serve as a basic handbook for researcher's engaged in this field.