It is a feature available only in Netsuite Oneworld. Multibook Accounting feature is used to maintain multiple set of accounting records based on a single set of real time transactions. There is primary book and secondary book in multibook accounting feature, accounting book which is maintained by the parent company is called primary book and accounting book which is maintained by the subsidiaries separately is called secondary book. In Multibook accounting a maximum of 5 active accounts book including the primary can be maintained. This feature includes the options such as chart of account mapping, foreign currency management, expense management and accounting book period close management. Records that are posted on all accounting books are called Book generic and records which posted to only one book usually used for book specific adjustments are called Book specific. Multibook Accounting feature helps an organization to comply with different accounting standards such as GAAP, IFRS and maintain separate books of accounts for their subsidiaries.
Setup > Company > Enable features > Under Accounting Subtab > Multibook Accounting
Note : Once the feature is enabled it cannot be disabled