This document reviews dictionary-based approaches to sentiment analysis. It discusses how sentiment analysis is used to determine sentiment polarity in text data using sentiment dictionaries like SentiWordNet. Dictionary-based methods involve matching words from a text to an opinion dictionary to determine if they express positive, negative, or neutral sentiment. The document also discusses some challenges with dictionary-based sentiment analysis, like handling negation and word sense disambiguation. Overall, the document provides an overview of dictionary-based sentiment analysis techniques and how they involve using sentiment dictionaries to classify the polarity of words and texts.