CUORE is a proposed tightly packed array of 1000 T eO 2 bolometers, each being a Preprint submitted to Elsevier Science 11 June 2018 cube 5 cm on a side with a mass of 760 g. The array consists of 25 vertical towers, arranged in a square of 5 towers by 5 towers, each containing 10 layers of 4 crystals. The design of the detector is optimized for ultralow-background searches: for neutrinoless double beta decay of 130 T e (33.8% abundance), cold dark matter, solar axions, and rare nuclear decays. A preliminary experiment involving 20 crystals 3 × 3 × 6 cm of 340 g has been completed, and a single CUORE tower is being constructed as a smaller scale experiment called CUORICINO. The expected performance and sensitivity, based on Monte Carlo simulations and extrapolations of present results, are reported.