Text-based games are complex, interactive simulations in which text describes the game state and players make progress by entering text commands. They are fertile ground for language-focused machine learning research. In addition to language understanding, successful play requires skills like long-term memory and planning, exploration (trial and error), and common sense. The talk will introduce TextWorld, a sandbox learning environment for the training and evaluation of RL agents on text-based games. Its generative mechanisms give precise control over the difficulty, scope, and language of constructed games, and can be used to study generalization and transfer learning. This talk will also give an overview of the recent attempts to solve text-based games either using reinforcement learning or more handcrafted approaches.