This document discusses inventory management. It defines inventory as materials obtained in advance of need that are held until used or sold. There are different types of inventories like raw materials, work in process, finished goods, and spare parts. Inventory valuation involves determining quality and assigning values. Costs associated with inventory include purchasing, ordering, holding, and shortage costs. The economic order quantity formula balances ordering and holding costs. Inventory control aims to have the right materials in the right quantity at the lowest cost through policies, stock levels, lead times, and order sizes.