That bulb is tied to the Illumination circuit in the car. Are any of your other interior lights out? I would start with testing for power and ground at the light socket. You would ideally want to use a multimeter with DC voltage capabilities.
If you use the meter as a load you will be able to test both the power supply and ground in one quick test as this is a very large circuit (think about all the switches and things that either change brightness or illuminate when the lights come on). If you have an auto ranging meter polarity isn't as essential, because the meter is not supplying any current.
Putting one lead in each of the back wire connectors (carefully) and measuring available DC voltage. You should have roughly battery voltage. If not then it is time to find out why. 
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