This document summarizes a research paper that proposes a method for sentiment analysis of customer reviews using a Hidden Markov Model. It first discusses how online retailers receive large numbers of customer reviews for products and how it is difficult to analyze the overall sentiment from all reviews. The proposed method involves using a Hidden Markov Model to analyze each review sentence and determine if it expresses a positive or negative sentiment. The model is trained on a dataset of customer reviews that have been part-of-speech labeled. Experimental results found that the trained Hidden Markov Model achieved high precision and accuracy in classifying the sentiment of reviews.