Part I The First Sources of Light.- Chapter 1 The Basic Theoretical Framework.- Chapter 2 The Epoch of Reionization.- Chapter 3 The First Stars.- Part II The First Galaxies and Normal Stellar Populations.- Chapter 4 Formation of the First Galaxies: Theory and Simulations.- Chapter 5 Observing the First Galaxies.- Chapter 6 The Formation of the First Massive Black Holes.- Part III Tools & Techniques.- Chapter 7 Evolutionary Synthesis Models as a Tool and Guide Towards the First Galaxies.- Chapter 8 Exploring the Universe with Metal-Poor Stars.- Chapter 9 The Potential Impact of Future Observatories.