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Many of the fundamental physical constants in Physics, as a discipline, aremeasured to exquisite levels of precision. The fundamental constants thatdefine Cosmology, however, are largely determined via a handful of independenttechniques that are applied to even fewer datasets. The history of themeasurement of the Hubble Constant (H0), which serves to anchor the expansionhistory of the Universe to its current value, is an exemplar of thedifficulties of cosmological measurement; indeed, as we approach the centennialof its first measurement, the quest for H0 still consumes a great number ofresources. In this white paper, we demonstrate how the approaching era ofExtremely Large Telescopes (ELTs) will transform the astrophysical measure ofH0 from the limited and few into a fundamentally new regime where (i) multiple,independent techniques are employed with modest use of large aperturefacilities and (ii) 1% or better precision is readily attainable. This quantumleap in how we approach H0 is due to the unparalleled sensitivity and spatialresolution of ELT's and the ability to use integral field observations forsimultaneous spectroscopy and photometry, which together permit both familiarand new techniques to effectively by-pass the conventional 'ladder' frameworkto minimize total uncertainty. Three independent techniques are discussed --(i) standard candles via a two-step distance ladder applied to metal, poorstellar populations, (ii) standard clocks via gravitational lens cosmography,and (iii) standard sirens via gravitational wave sources -- each of which canreach 1% with relatively modest investment from 30-m class facilities.

Measuring the Hubble Constant Near and Far in the Era of ELT's