Environmentally oriented modernization of power boilers explains how to retrofit and upgrade power boilers in aging thermal and CHP plants, with emphasis on pulverized fuel boilers (PF). The work provides direct avenues to higher boiler efficiency, harmful emissions reduction, fuel grinding system modernization, fuel flexibility, boiler operation flexibilization, reduced corrosion, erosion, and fouling. It also explores how to integrate emission reduction systems into boiler operations. The work is planned for engineers and graduate students as well as for power plant management. For the latter, it helps find the best solution for the necessary modernization and functions as an aid in organizing tenders as well as in evaluating projects offered. Errata to published editions can be found here https://modernpowerboilers.org/errata.html Presents, in a clear and accessible way, the most important solutions related to boiler emissions reduction, including CO2 emissions Helps increase boiler efficiency through technical and operational upgrades Helps increase the usefulness of boilers by increasing fuel and operational flexibility Supports reduction of harmful phenomena, such as corrosion, erosion, and fouling Accompanied with a careful selection of realized modernizations, including pitfalls and best practice discussion Chapters are presented alongside hundreds of literature references for further study