book·keep·er
 /ˈbʊkˌkiːpɚ/  noun  ,  pl   -ers [  count  ]
  : a person whose job is to keep the financial records for a business
  book·keep·ing /ˈbʊkˌkiːpıŋ/  noun   [  noncount  ]
   He does the bookkeeping.
   a bookkeeping error