TAP, the Transient Astrophysics Probe, was selected by NASA for a Astrophysics Probe Mission Concept Study in 2017. TAP is an observatory designed to greatly advance our astrophysical understanding of the transient Universe. TAP is multi-instrument platform, sensitive to a broad variety of astrophysical phenomena across the entire sky, with rapid transient follow up with high sensitivity over a broad energy range. The baseline complementary instrument suite comprises wide-field X-ray and gamma-ray monitors, a high-resolution sensitive X-ray telescope, and a wide-field infrared telescope. This combination will discover transients deep into the Universe, and enable astrophysical characterization through broadband observations. TAP science is directly responsive to the goals set forth by the Astro2010 Decadal Survey and the NASA Astrophysics Roadmap in the areas of time domain astrophysics and gravitational waves.