Domain wall nanoelectronics is a rapidly evolving field that explores the unique properties and applications of domain walls in ferroic materials, including ferroelectrics, ferromagnets, and multiferroics. Traditional understanding of domain walls in ferroelectrics was limited to simple, Ising-like structures, but recent advances in atomic-resolution studies have revealed their complex behavior. These studies have uncovered new functional properties within domain walls, particularly in magnetoelectric materials, where domain wall conductivity and magnetic properties are being directly measured. This review focuses on ferroelectrics and multiferroics, while making comparisons with magnetic domains and domain walls. Domain walls are boundaries between adjacent domains and play a crucial role in the behavior of ferroic materials. The size and properties of domains are determined by the competition between domain energy and domain wall energy. Kittel's law, which describes the square root dependence of domain width on film thickness, is a fundamental concept in this field. However, recent studies have shown that this law has limitations, particularly in cases involving surface effects, critical thickness, and superlattices. Domain walls in ferroic materials can have different symmetries and properties from the domains they separate. This distinction is important for understanding the behavior of thin films and nanoscale devices. In particular, magnetic domain wall microelectronics is already in full swing, with devices exploiting the high mobility of magnetic domain walls. These devices can achieve supersonic velocities, as demonstrated by Kreines' and co-workers. In contrast, nanoelectronic devices using ferroelectric domain walls often have slower domain wall speeds, but may exploit their smaller size and different functional properties. These include domain wall conductivity, which can be metallic or superconducting in certain materials, and the fact that domain walls can be ferromagnetic while the surrounding domains are not. The review also discusses various domain topologies, including stripes, vertices, vortices, and quadrupoles, and their implications for the behavior of ferroic materials. These structures are important for understanding the functional properties of domain walls and their potential applications in nanoelectronics and other technologies. The study of domain walls is not limited to ferroics but also includes magnetic and multiferroic systems, where the interplay between different order parameters can lead to novel phenomena. Overall, the review highlights the importance of domain walls in ferroic materials and their potential for future device applications. The unique properties of domain walls, such as their mobility and functional characteristics, make them promising candidates for next-generation electronic devices. The study of domain walls is an active area of research, with ongoing efforts to understand their behavior and harness their properties for technological applications.Domain wall nanoelectronics is a rapidly evolving field that explores the unique properties and applications of domain walls in ferroic materials, including ferroelectrics, ferromagnets, and multiferroics. Traditional understanding of domain walls in ferroelectrics was limited to simple, Ising-like structures, but recent advances in atomic-resolution studies have revealed their complex behavior. These studies have uncovered new functional properties within domain walls, particularly in magnetoelectric materials, where domain wall conductivity and magnetic properties are being directly measured. This review focuses on ferroelectrics and multiferroics, while making comparisons with magnetic domains and domain walls. Domain walls are boundaries between adjacent domains and play a crucial role in the behavior of ferroic materials. The size and properties of domains are determined by the competition between domain energy and domain wall energy. Kittel's law, which describes the square root dependence of domain width on film thickness, is a fundamental concept in this field. However, recent studies have shown that this law has limitations, particularly in cases involving surface effects, critical thickness, and superlattices. Domain walls in ferroic materials can have different symmetries and properties from the domains they separate. This distinction is important for understanding the behavior of thin films and nanoscale devices. In particular, magnetic domain wall microelectronics is already in full swing, with devices exploiting the high mobility of magnetic domain walls. These devices can achieve supersonic velocities, as demonstrated by Kreines' and co-workers. In contrast, nanoelectronic devices using ferroelectric domain walls often have slower domain wall speeds, but may exploit their smaller size and different functional properties. These include domain wall conductivity, which can be metallic or superconducting in certain materials, and the fact that domain walls can be ferromagnetic while the surrounding domains are not. The review also discusses various domain topologies, including stripes, vertices, vortices, and quadrupoles, and their implications for the behavior of ferroic materials. These structures are important for understanding the functional properties of domain walls and their potential applications in nanoelectronics and other technologies. The study of domain walls is not limited to ferroics but also includes magnetic and multiferroic systems, where the interplay between different order parameters can lead to novel phenomena. Overall, the review highlights the importance of domain walls in ferroic materials and their potential for future device applications. The unique properties of domain walls, such as their mobility and functional characteristics, make them promising candidates for next-generation electronic devices. The study of domain walls is an active area of research, with ongoing efforts to understand their behavior and harness their properties for technological applications.