The aim of this third Eng Special Issue was to bring together experimental and theoretical research relating to engineering science and technology. The topics included in Eng are as follows: electrical, electronic, and information engineering; chemical and materials engineering; energy engineering; mechanical and automotive engineering; industrial and manufacturing engineering; civil and structural engineering; aerospace engineering; biomedical engineering; geotechnical engineering and engineering geology; and ocean and environmental engineering. Many of these topics were selected with the aim of contributing to the circular economy and sustainable development. Therefore, the above aspects are addressed from various points of view and have the support of the field of engineering and its applications.