"Sentiment Analysis - From Theory to Practice" is a specialized book that focuses on the analysis of opinions and sentiments in various information systems. It highlights the challenges and opportunities presented by sentiment-aware applications and provides a comprehensive overview of methods for classifying and extracting opinions. The book goes beyond traditional fact-based analysis and also addresses multimodal approaches that incorporate text, images, and other media. Additionally, it presents various methods for summarizing critical texts to enhance the efficiency of information retrieval. The authors also discuss the financial implications arising from the development of opinion-oriented information access services and offer insights into future trends in sentiment analysis. This book is aimed at students, researchers, and professionals interested in this subject matter.