Anaesthesia involves inducing a state where patients do not feel pain during medical procedures. Balanced anaesthesia uses multiple anaesthetic agents and techniques together for improved safety and control. There are different types including general anaesthesia which induces unconsciousness, regional which blocks pain in parts of the body, and local which numbs small areas. Anaesthesia has phases including induction to induce the state, maintenance to keep the patient anaesthetized during a procedure, and recovery as the effects wear off.