This book contains a record of all the vouchers and entries representing the transactions of each day. Theoretically, the particulars of every item in the cash book should be entered in detail, but owing to the wide extension of banking facilities and the constantly increasing volume of checks and other entries, it has been found necessary to use supplementary books for recording particulars of any class of items whose volume is sufficient to warrant a separate book - only the day's totals are carried into the general cash book. The majority of entries, especially in a large office, are therefore in the form of totals, and very few detailed entries have to be made; but all entries, when made, should be definite as to source and sufficiently self-explanatory to be understood by any one at any time - ten years after, if necessary.

In the larger offices, the officers in charge of the different departments after balancing their books hand to the cash-book clerk the totals in the form of a signed memorandum, and even in the smaller offices it is advisable to have the clerks entering up the various supplementary books, give a similar memorandum of their totals. This limits the responsibility and adds to the efficiency of the staff.

Debit and credit entries for cash book, other than the totals referred to above, are represented by vouchers giving the necessary particulars, signed by the manager, accountant or other authorized officer, and it should be an imperative rule that any slip, which does not contain sufficient particulars or which lacks the necessary signature, should be refused by the cash-book clerk and referred back to the teller for completion. In order to facilitate the sorting and checking of these vouchers, distinctive colored paper or printing should be used; for instance, yellow, debit slips and white, credit slips.

It should constantly be borne in mind that as the cash book and its supplementary books are recognized in a court of law as the books of original entry, faulty or meager particulars might cause serious trouble. Verbal explanation, even if available, would not be admitted. Examine a bank cash book of twenty or thirty years ago: there could be no better object lesson of what a cash book should be. Copper-plate writing and ample particulars are characteristic.