**1. Introduction and Scope**

Laser Shock Processing (LSP) is continuously developing as an effective technology for improving the surface and mechanical properties of metallic alloys and is emerging in direct competition with other established technologies, such as shot peening, both in preventive manufacturing treatments and maintenance/repair operations.

The level of maturity of Laser Shock Processing has been increasing during the last few years, and several thematic international conferences have been organized (the 7th ICLPRP held in Singapore, June 17–22, 2018, being the last reference), where different developments on a number of key aspects have been discussed, i.e.:


All these aspects have been recursively treated by well-renowned specialists, providing a firm basis for the further development of the technology in its path to industrial penetration.

However, the application of LSP (and related technologies) to different types of materials, envisaging different types of applications (ranging from the always demanding aeronautical/aerospatial field to the energy generation, automotive, and biomedical fields), still requires extensive effort in the elucidation and mastering of different critical aspects, thus deserving a grea<sup>t</sup> research effort as a necessary step prior to its industrial readiness level.

The present Special Issue of *Metals* in the field of "Laser Shock Processing and Related Phenomena" aims, from its initial launching date, to collect (especially for the use of LSP application developers in the different target sectors) a number of high-quality and relevant papers representing present state-of-the-art technology also useful to newcomers in realizing its wide and relevant prospects as a key manufacturing technology.

Consequently, and in an additional and complementary way to papers presented at the thematic ICLPRP conferences, a call was made to those authors willing to prepare a high-quality and relevant paper for submission to the journal, with the confidence that their work would become part of a fundamental reference collection providing the present state-of-the-art LSP technology.

The result is now available and the Special Issue has been completed, with two review and nine full research papers, really setting reference knowledge for LSP technology and covering the practical totality of open issues leading the present-day research at worldwide universities, research centers, and industrial companies.
