The cyclic calcium oxide-calcium carbonate (CaO-CaCO3) process is a promising option for large-scale CO2 control. Important advantages include high-temperature operation, inexpensive sorbent feedstock, and high CO2 capture capacity of CaO. However, decreasing sorbent reactivity over multiple cycles, due to high-temperature sintering, presents a major challenge for further progress. The Ohio State University (OSU) has led the development of a novel three-step calcium looping (CaO-Ca(OH)(2)-CaCO3) process for post- and precombustion CO2 capture. An overview of OSU's work is provided, highlighting the differences in this approach when compared to competing efforts in this field.