Intelligent agents are software entities which can carry out some actions on behalf of clients with some degree of autonomy. Through sensing the status of environment, agents perform some operations based on some possessed knowledge in order to change or influence the environment towards their goals. A Multi-Agent System (MAS) is a group or society of agents, and agents interact with others in the group cooperatively and/or competitively in order to reach their individual or common goals. In general, agents possess five common properties which are autonomy (some level of self-control), adaptivity (the ability to learn and improve performance with experience), reactivity (the ability to perceive the environment and to respond in a timely fashion to changes that occur), proactivity (the ability not only to act simply in response to their environment but also to exhibit goal-directed behaviour by taking the initiative) and sociability (the ability to interact, communicate and work with other agents). Research on agent techniques and MASs mainly focus on improving existing or invent innovative frameworks, models, mechanisms, approaches and algorithms to improve agents effectiveness and efficiency in those five aspects for advanced autonomous problem solving abilities in complex environments.