Californians are very concerned about funding for their K-12 public schools. They consistently say that K-12 education should be protected from spending cuts over and above any other area of the state budget. California's system of school finance is in trouble. Many studies have found it to be inequitable, with wide variation in per-pupil funding. Prominent critics charge that schools do not receive enough resources from the state to enable all students to meet California's academic standards. The system is governed by such a complex array of laws and formulas that only a few experts truly understand how it works. This paper describes California's school finance system, reviews its key challenges, offers principles for reform, and outlines pathways toward a more equitable, adequately funded, and transparent system. (Contains 3 tables, 2 figures and 29 notes.)