Deep learning techniques have had a huge impact on artificial intelligence research. They have improved upon the traditional machine learning techniques where human expertise was required for feature engineering. By removing one human factor, they have moved us one step forward in the field of artificial intelligence. They have not entirely removed humans, though. They are required for designing the architectures and cleaning the data. Deep learning techniques have managed to achieve breakthrough results in domains such as speech recognition, machine translation, image recognition, and object detection. This chapter gives a brief overview of various deep learning techniques being used today. Techniques that make deep learning more effective have been described. Some interesting applications have also been covered.