Yes, invoice summary can be used for book keeping purposes. Inorder to view invoice summary, click on invoices from left hand side navigation and then click List. Page similar to below image will be displayed. Top section will display summary information Total Invoiced (Sales) and Tax, Paid, Unpaid and Overdue amounts.
Finally, for reconciling purpose in your accounting software (eg : MYOB, Xero etc), you can make journal entries per month or fortnight into bookkeeping software summary information.
Note: Change the period using date period selector to capture summary information.