Over-the-top content delivery is becoming increasingly attractive for both live and on-demand content thanks to the popularity of platforms like YouTube, Vimeo, Netflix, Hulu, Maxdome, etc. In this tutorial, we present state of the art and challenges ahead in over-the-top content delivery. In particular, the goal of this tutorial is to provide an overview of adaptive media delivery, specifically in the context of HTTP adaptive streaming (HAS) including the recently ratified MPEG-DASH standard. The main focus of the tutorial will be on the common problems in HAS deployments such as client design, QoE optimization, multi-screen and hybrid delivery scenarios, and synchronization issues. For each problem, we will examine proposed solutions along with their pros and cons. In the last part of the tutorial, we will look into the open issues and review the work-in-progress and future research directions.