Observations indicate that our universe can be characterised by three distinct phases of evolution: An early inflationary phase, possibly driven by a scalar field, a late-time accelerated phase dominated by dark energy, and a transient phase in between, dominated by radiation and matter. The late-time acceleration can be consistently modelled in terms of a cosmological constant (Λ) provided its value is extremely tiny: ΛL_P^2 ≈ 10^{-122} where L_P = (Għ/c^3)^{1/2} is the Planck length. Two key issues in theoretical physics are to explain (a) why gravity is immune to changes in the bulk energy that could contribute to Λ and (b) why this dimensionless parameter ΛL_P^2 has such an extremely small value. I will describe how these questions can be answered in the backdrop of a paradigm which treats gravity is an emergent phenomenon with its field equations having the same conceptual status as, for example, the equations of elasticity or fluid mechanics. This approach provides a unified picture of cosmic evolution relating the early inflationary phase, the late accelerating phase and the holographic features of Planck scale physics. I will also discuss how these ideas are related to a description of cosmic expansion as a quest for holographic equipartition and lead to a novel paradigm to study cosmology.”