The Kepler Mission began its 3.5-year photometric monitoring campaign in May 2009 on a select group of approximately 150,000 stars .
The stars were chosen from the \sim half million in the field of view that are brighter than 16th magnitude .
The selection criteria are quantitative metrics designed to optimize the scientific yield of the mission with regards to the detection of Earth-size planets in the habitable zone .
This yields more than 90,000 G-type stars on or close to the Main Sequence , > 20 , 000 of which are brighter than 14th magnitude .
At the temperature extremes , the sample includes approximately 3,000 M-type dwarfs and a small sample of O and B-type MS stars ( < 200 ) .
Small numbers of giants are included in the sample which contains \sim 5,000 stars with surface gravities \log ( g ) < 3.5 .
We present a brief summary of the selection process and the stellar populations it yields in terms of surface gravity , effective temperature , and apparent magnitude .
In addition to the primary , statistically-derived target set , several ancillary target lists were manually generated to enhance the science of the mission , examples being : known eclipsing binaries , open cluster members , and high proper-motion stars .