Required by most states, liability coverage is the foundation of any auto insurance policy.  In case of an accident where you are found to be at fault, your liability insurance pays for the bodily injury and property damage expenses you cause to others, as well as any legal fees in the case of a lawsuit. 

Liability coverage limits are generally presented as a series of three numbers, for example 20/40/10.  Here those numbers would represent coverage limits of $20,000 for bodily injury sustained by one person injured in an accident, $40,000 for total bodily injuries sustained when more than one person is injured in one accident, and $10,000 for total property-damage resulting from one accident.  When comparing car insurance providers, if you do nothing else, make sure all the policies being priced are showing the same three numbers here.