WordNet (r) 3.0 (2006):

workbook
    n 1: a student's book or booklet containing problems with spaces
         for solving them

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "workbook":
   Domesday Book, abecedarium, abecedary, account book, address book,
   adversaria, album, alphabet book, annual, appointment calendar,
   appointment schedule, battledore, blankbook, blotter, calendar,
   casebook, cashbook, catalog, classified catalog, commonplace book,
   court calendar, daybook, desk calendar, diary, diptych, docket,
   engagement book, exercise book, gradus, grammar, hornbook, journal,
   ledger, log, logbook, loose-leaf notebook, manual,
   manual of instruction, memo book, memorandum book, memory book,
   notebook, pad, petty cashbook, pocket notebook, pocketbook,
   police blotter, primer, reader, schoolbook, scrapbook, scratch pad,
   speller, spelling book, spiral notebook, t, table, tablet, text,
   triptych, writing tablet, yearbook