Comets: Clues to our Solar System's Beginnings and Life on Earth Our solar system formed from a vast interstellar cloud of gas and dust four and a half billion years ago. The direct record of this formation has largely been erased, however, the best preserved clues to the chemical and physical conditions at the time of formation are preserved in the small icy bodies which we observe today as comets. Comets are the left-over remnants of the planetary building process in the cold outer regions of our solar system. We humans, and all life on Earth, are aqueous beings. Water's chemical properties and the way it responds to changes in temperature make it an ideal medium for biological activity, so much so that it is considered essential for recognizable life. Cosmically, water is not uniformly abundant, and its incorporation into Earth-size planets is not necessarily constant. Water is abundant on present-day Earth. What was the origin of this water and how did it become incorporated in the Earth? The total inventory and distribution of water on Earth was probably determined early in the planet's history and may have been delivered by impacts of comets or planetesimals forming in the vicinity of today's asteroid belt, and we have clues to the origin of water on Earth from observations of the chemical make up of comets in comparison with ocean water. This talk will present a general overview of the history of comet observations, leading up to modern observations of bright comets with the world's largest telescopes. A brief overview of upcoming space missions to comets will show how modern tools will be exploring the clues to our past, and a discussion of a new program to look at the cometary contribution to Earth's water inventory (oceans) will be presented.