This article provides an overview of the content in the issue of *MRS Bulletin* focusing on Cellular Solids. It highlights the unique properties and applications of natural and engineered cellular solids, such as cork, wood, sponge, bone, and materials like polymers, metals, ceramics, and glasses. The articles in this issue cover the fabrication, structure, properties, and applications of porous solids, including cellular ceramics, metallic foams, and scaffolds for tissue engineering. The mechanical behavior of these materials is discussed, emphasizing their ability to withstand large strains at nearly constant stress, making them suitable for energy absorption and thermal insulation. The issue also explores advanced techniques for understanding, modeling, and measuring the behavior and properties of cellular solids, including finite element analysis and microcomputed tomography. The applications of these materials in lightweight construction, impact-energy absorption, acoustic damping, and heat transfer are detailed, along with their use in biomedical applications such as tissue engineering.This article provides an overview of the content in the issue of *MRS Bulletin* focusing on Cellular Solids. It highlights the unique properties and applications of natural and engineered cellular solids, such as cork, wood, sponge, bone, and materials like polymers, metals, ceramics, and glasses. The articles in this issue cover the fabrication, structure, properties, and applications of porous solids, including cellular ceramics, metallic foams, and scaffolds for tissue engineering. The mechanical behavior of these materials is discussed, emphasizing their ability to withstand large strains at nearly constant stress, making them suitable for energy absorption and thermal insulation. The issue also explores advanced techniques for understanding, modeling, and measuring the behavior and properties of cellular solids, including finite element analysis and microcomputed tomography. The applications of these materials in lightweight construction, impact-energy absorption, acoustic damping, and heat transfer are detailed, along with their use in biomedical applications such as tissue engineering.