<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-12-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000107140</issuerCik>
        <issuerName>WILEY JOHN &amp; SONS, INC.</issuerName>
        <issuerTradingSymbol>jwa</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001302993</rptOwnerCik>
            <rptOwnerName>Jones Kim</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>SUN MICROSYSTEMS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>15 NETWORK CIRCLE, MAILSTOP MPK15-204</rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>42.57</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-12-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>33.04</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>42.57</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>33.04</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10115.07</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents additional shares of Phantom Stock as a result of a quarterly dividend.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Michael L. Preston for Kim Jones</signatureName>
        <signatureDate>2009-12-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0303
4
2009-12-30
0
0000107140
WILEY JOHN & SONS, INC.
jwa
0001302993
Jones Kim
SUN MICROSYSTEMS, INC.
15 NETWORK CIRCLE, MAILSTOP MPK15-204
MENLO PARK
CA
94025
1
0
0
0
Phantom Stock Units
42.57
2009-12-28
4
A
0
33.04
42.57
A
Class A Common
33.04
10115.07
D
Represents additional shares of Phantom Stock as a result of a quarterly dividend.
Michael L. Preston for Kim Jones
2009-12-30