The Low Frequency Array is a new radio telescope based on phased array principles that will operate at frequencies from 10–240 MHz. The vast improvement in sensitivity and resolution over previous instruments that have worked at these frequencies, together with the increased flexibility that results from the phased array approach (multi-beaming, no moving parts) make LOFAR an extremely versatile and powerful new instrument. We present some of the scientific drivers and give an overview of the current design.