This book focuses on the following areas, focusing on solutions to past year's problems, to help test takers develop their skills and pass the written exam in a short period of time.

First, the core contents were included by classifying them into five subjects: gas fluid dynamics, combustion engineering, gas facilities, gas safety management, and gas measurement.
Second, previous year's exam questions are included with detailed explanations and calculation formulas.
Third, the core content was summarized and the solutions to the questions were explained using a mixture of engineering units and SI units.
Fourth, the author personally opened and managed a cafe where students could share exam information along with questions and answers online.
Cafe: Questions and Answers on Seo Sang-hee's Textbook (http://cafe.naver.com/gas21)