The Future of CMB Polarization Measurements from the Stratosphere and the Ground

Recent advances in instrumentation are enabling increasingly precise measurements of the Cosmic Microwave Background (CMB), which have the potential to transform our understanding of the Universe.  In this talk I will discuss scientific prospects and technological developments for two upcoming experiments: Taurus and CMB-S4.  Taurus is a proposed balloon-borne telescope designed to study the epoch of reionization from a superpressure balloon.  CMB-S4 is an upcoming ground-based experiment, consisting of dedicated telescopes operating from multiple sites to map a large fraction of the sky in many frequency bands. These complementary experiments will measure the CMB polarization over a wide range of angular scales and probe many outstanding cosmological questions ranging from the nature of dark energy to the characteristics of fundamental particles.