Book excerpt: Topology optimization (TO) is an automated design tool that integrates mathematical modeling with numerical analysis to automatically reduce weight and material usage while ensuring certain prescribed constraints on performance of the design are satisfied. The high-performance light-weight designs created through topology optimization are often free-form and organic, manufacturing of which through traditional casting, forming, or subtractive technologies can become quite challenging. Additive manufacturing (AM) is a class of more modern technologies that seem to alleviate this issue by fabricating complex parts layer by layer. On the other hand, the cost of additively manufactured parts increase significantly with material usage. Therefore, optimizing designs can reduce material usage, build time, and post-process time to make AM worthwhile. Thus, TO and AM complement each other to fabricate ever more complex high performance and customized yet affordable products. However, for these technologies to be integrated, there are certain issues, such as extraneous support structures or material anisotropy, that need to be considered within the optimization. Focus of this thesis is mainly on: 1. Addressing challenges on reducing amount of support structure and considering process-induced anisotropy throughout the optimization process. 2. Exploiting the capabilities of AM in free-form fabrication to improve performance by generating more complex multi-material designs. In other words, the present thesis attempts to make advances on integrating the two modern and promising fields, topology optimization and additive manufacturing by developing optimization algorithms that generate optimized designs while tracing Pareto frontiers. Perhaps the most important benefit of this class of methods is the fact that intermediate topologies remain structurally valid, thus iterative solvers can converge much faster. Further, these intermediate designs are local optimum solutions. These traits make these methods well-suited for rapidly exploring the design space to find freeform designs while ensuring their structural integrity.