The book of a major Polish scientist S. Bretschneider is devoted to the description of engineering methods for calculating the properties of gases and liquids. Methods for calculating the following properties are considered: viscosity, diffusion and thermal conductivity of gases and liquids; surface tension and heat of evaporation of liquids; critical constants. The book sets out the main theoretical principles, as well as many reference tables, nomograms based on the latest literature, and examples.