Additive manufacturing (AM) is one of the emerging manufacturing techniques of immense engineering and scientific importance and is regarded as the technique of the future [1-3]. AM can fabricate any kind of material, including metals, polymers, ceramics, composites, etc. Selective laser melting (SLM), also known as the laser-based powder bed fusion process (LPBF), is the most widely used AM techniques that can fabricate a wide variety of materials, including Al-based [4-6], Fe-based [7-10], Ti-based [11][12][13], Co-based [14-16], Cu-based [17][18][19] and Ni-based alloys [20][21][22], etc. Similar to any AM processes, the SLM/LPBF process also offers several advantages, like added functionality, near-net-shape fabrication with minimal or no post-processing, shorter lead-time, offer intricacy for free, etc. [23][24][25]. The SLM process has its applications in the aerospace, automobile, oil refinery, marine, construction, food and jewelry industries, etc. [26][27][28]. However, there exist some shortcomings in the SLM field, which are (a) SLM-based alloy development [29], (b) the premature failure of materials, even though improved properties are observed [30], (c) process innovation and development, (d) structure-property correlation and (e) numerical simulations, etc.Accordingly, the present Special Issue (book) focuses on the two main aspects: materials and applications. Alloy design and development that suits the specific process conditions is essential, rather than using the conventionally designed/available materials. The application spectrum is getting wider day by day, hence the need for our attention. Overall, six articles are published under this Special Issue, with the following themes: