Theft, or larceny, is the unlawful taking of someone else's property with the intent to permanently (sometimes even temporarily) deprive them of it. In California, theft crimes are codified in a variety of places, and not exclusively in the Penal Code.
Common types of theft include petty theft, grand theft, auto theft, embezzlement, possession of stolen property, theft by fraud, and identity theft. Most theft crimes are considered to be non-violent offenses. Robbery, which of course is theft by force or fear, is a violent offense and discussed elsewhere in my website. Even non-violent theft offenses are serious crimes, and people convicted of felony theft offenses are exposed to a commitment to state prison or to lengthy local jail terms under Penal Code section 1170, subdivision (h).
Due to the many different forms of theft crimes and their different elements, the complexity of defending them is best left to a professional. I am ready to consult with you if you or someone you care about is facing prosecution for any of the many theft offenses.