4 letters:
book, cook, hook, look, mook, nook, rook, took, zook

5 letters:
anouk, blook, booke, brook, chook, chuuk, cooke, crook, drook, ebook, flook, hbook, hooke, ibook, krook, plook, quook, rooke, shook, snook, sooke, stook, tooke

6 letters:
abrook, acrook, a look, betook, brooke, crooke, decook, e-book, gov.uk, hanguk, istook, kabook, kirkuk, krupuk, mccook, nanook, p-book, rebook, relook, retook, schook, shnook, shtook, strook, talook, unbook, unlook, uplook

7 letters:
boobook, chinook, docbook, eyehook, flybook, forsook, kedlook, lawbook, liphook, logbook, macbook, mistook, netbook, nonbook, nuthook, olicook, on-hook, outlook, partook, pothook, prebook, precook, prelook, redbook, runbook, schnook, skyhook, stroock, suncook, tiphook, vanhook, vpnbook, webhook, wetlook, zam-buk, zenbook, zoolook

8 letters:
ashbrook, bankbook, benbrook, billhook, bluebook, boathook, casebook, cashbook, chapbook, codebook, cookbook, copybook, datebook, day book, dimitruk, domebook, dynabook, facebook, fishhook, flipbook, foothook, forehook, forelook, fry cook, fuckbook, gamebook, gowdnook, griphook, han-gook, handbook, herdbook, holbrook, hornbook, hymnbook, islam4uk, jokebook, jungkook, kravchuk, laibrook, log-book, lookbook, maksymuk, meathook, mug book, nainsook, notebook, oakbrook, off-hook, omnibook, overbook, overcook, overhook, overlook, overtook, passbook, porthook, ravehook, roadbook, rulebook, saybrook, seabrook, shopbook, sihanouk, songbook, soulbook, studbook, tailhook, textbook, timbrook, tim cook, toolbook, wet-look, wordbook, workbook, yearbook

9 letters:
allsbrook, aroostook, audiobook, bell book, blankbook, blue-book, blue book, boat hook, cant hook, cash-book, chap-book, checkbook, claybrook, colebrook, copy-book, cranbrook, dope-book, estabrook, fake book, fallbrook, fire hook, fish-hook, glenbrook, good book, grasshook, guestbook, guidebook, hasbrouck, hautelook, horn-book, hornbrook, inglenook, lashbrook, leaf-book, matchbook, millbrook, news-book, note-book, overbrook, pennacook, philbrook, phonebook, pitchbook, pixelbook, powerbook, psalmbook, reap hook, rosebrook, scorebook, scrapbook, sheephook, shredcook, side-look, smartbook, storybook, stylebook, superbook, swinbrook, tablebook, text-book, thinkbook, tillamook, toughbook, ultrabook, undercook, underhook, undertook, wastebook, westbrook, year-book

10 letters:
a. j. cook, absey-book, black book, breasthook, buttonhook, carisbrook, chequebook, chromebook, comic book, coursebook, donnybrook, dotori-muk, elderbrook, get a look, glazebrook, kinderhook, micro-cook, needlebook, northbrook, order book, phone book, photo-book, phrasebook, pocketbook, prayerbook, promptbook, schoolbook, shiftylook, shirebrook, sketchbook, sourcebook, sparkbrook, sportsbook, stainbrook, table-book, tenterhook, trade book, vandercook, white book

11 letters:
beaverbrook, bolingbrook, cheque-book, closed book, double-book, easterbrook, fictionbook, hardenbrook, have a look, meadowbrook, middlebrook, millerbrook, minute book, pastry cook, phrase book, prayer book, prompt-book, pumblechook, sarah snook, source book, subnotebook, take a look, thefacebook, throw-crook, ticket book, willowbrook

12 letters:
account book, chingachgook, crochet hook, gobbledegook, gobbledygook, kim jae-wook, olivia cooke, picture-book, picture book, pruning hook, reaping-hook, reaping hook, service book, statute book, talking book, the babadook, the notebook

13 letters:
coloring book, create-a-book, ji chang-wook, lee dong-wook, pressure-cook

14 letters:
grappling hook, park chan-wook, reference book, telephone book

15 letters:
shepard's crook

16 letters:
appointment book, bryce papenbrook, commonplace book, dae-han-min-gook, instruction book, travel guidebook

17 letters:
russell westbrook

18 letters:
legislation.gov.uk, zac stubblety-cook

19 letters:
by hook or by crook, history of facebook, wombat.doc.ic.ac.uk

20 letters:
boeing ch-47 chinook