Abstract: The checkbook comprises a flexible, foldable cover having a series of spaced pins along one edge to which a journal sheet is releasably attachable by inserting spaced openings in the edge of the sheet over the pins. Data is recordable in a plurality of horizontal rows of data boxes or spaces, which are printed on the face of the journal sheet, by placing a check over the sheet so that a row of data boxes on the check register vertically with a selected row of data boxes on the face of the journal sheet. Each check also has openings along one edge insertable over the pins on the cover releasably to hold the check in a desired position on the journal sheet. A strip of carbon backing on the back of each check registers with the data boxes on the face of the check and overlies the corresponding boxes on the journal sheet so that data entered on the check face is entered simultaneously on the journal. Two alternative means for securing the journal sheets and checks on the cover are also disclosed.