Introduction

This chapter covers the historical basis of the quest for a theory of quantum gravity. The discussion includes the development of quantum theory in parallel with general relativity and the realisation that results like the area-entropy law for black holes hinted at a connection between statistical mechanics and gravitational physics. An overview of ideas in the field of quantum gravity research, such as string theory, causal set theory, and causal dynamical triangulations is provided to place loop quantum gravity in the wider context of this endeavour.