ABC analysis is an inventory categorization method that divides items into three categories - A, B, and C - based on their value and volume. Category A items are the most valuable, making up 20% of inventory items but 80% of total value. Category B items are next most valuable, comprising 30% of items and 15% of value. Category C items are least valuable, representing 50% of items but only 5% of total value. The method aims to focus management attention on the critical high-value Category A items rather than the many low-value Category C items.