LANE ALTMAN & OWENS LLP      101 Federal Street              Telephone
     Counsellors at Law        Boston, Massachusetts 02110     (617) 345-9800

                                                               Telefax
                                                               (617) 345-0400



                                                               March 1, 1999

Gordon Altman Butowsky
 Weitzen Shalov & Wein
114 West 47th Street
New York, NY 10036


Dear Sirs:

     We understand that the trustees of Morgan Stanley Dean Witter Income
Builder Fund, a Massachusetts business trust (the "Trust"), intend, on or about
March 1, 1999, to cause to be filed on behalf of the Trust a Registration
Statement on Form N-14 (the "Registration Statement") in connection with the
acquisition (the "Acquisition") by the Trust of substantially all the assets of
TCW/DW Income and Growth Fund ("Income and Growth"), in exchange for shares of
beneficial interest of the Trust (the "Shares"), and the assumption by the
Trust of certain stated liabilities of Income and Growth pursuant to an
Agreement and Plan of Reorganization dated as of February 25, 1999 (the
"Agreement"). We further understand that the Shares will be issued pursuant to
the Agreement.

     You have requested that we act as special counsel to the Trust with
respect to the laws of the Commonwealth of Massachusetts on certain specified
matters, and in such capacity we are furnishing you with this opinion. You have
not asked for, and we do not offer, an opinion on any other matter or
transaction related to the Trust, Income and Growth, the Acquisition, the
Agreement or any matter related thereto, except as specifically set forth
below.

     The Trust is a business trust created under an Agreement and Declaration
of Trust finally executed, delivered and filed in Boston, Massachusetts on
March 21, 1996 (as amended from time to time, the "Trust Agreement"). The
Trustees of the Trust (as defined in the Trust Agreement) (the "Trustees") have
the powers set forth in the Trust Agreement, subject to the terms, provisions
and conditions provided therein.

     In connection with our opinions delivered herein, we have examined the
following items some of which have been provided to us by, or on behalf of,
you: (i) a copy of the Agreement in the form to be executed by the Trust; (ii)
a copy of the Trust Agreement; (iii) a copy of the Amended and Restated By-laws
of the Trust effective as of January 28, 1999; (iv) a Certificate of Legal
Existence for the Trust provided by the Secretary of State of the Commonwealth
of Massachusetts dated February 24, 1999; and (v) copies of the Registration
Statement on Form N-14 to be filed by the Trust and the Trust's current
Prospectus and Statement of Additional Information.

     In rendering this opinion we have assumed, without independent
verification, (i) the due authority of all individuals signing in
representative capacities and the genuineness of signatures, (ii) the
authenticity, completeness and continued effectiveness of all documents or
copies furnished to us, (iii) that resolutions approving the Registration
Statement, the Acquisition and the Agreement have been duly adopted by the
Trustees, (iv) that no amendments, agreements, resolutions or actions have been
 


approved, executed or adopted which would limit, supersede or modify the items
described above, and (v) that the by-laws filed as an exhibit to the
Registration Statement have been duly adopted by the Trustees. We have also
examined such questions of law as we have concluded necessary or appropriate
for purposes of the opinions expressed below. Where documents are referred to
in resolutions approved by the Trustees, or in the Registration Statement, we
assume such documents are the same as in the most recent form provided to us,
whether as an exhibit to the Registration Statement, or otherwise. When any
opinion set forth below relates to the existence or standing of the Trust, such
opinion is based entirely upon and is limited by the items referred to above.
We understand that the foregoing assumptions, limitations and qualifications
are acceptable to you.

     Based upon the foregoing, and with respect to Massachusetts law only
(except that no opinion is herein expressed with respect to compliance with the
Massachusetts Uniform Securities Act), to the extent that Massachusetts law may
be applicable, and without reference to the laws of any of the other several
states or of the United States of America, including State and Federal
securities laws, we are of the opinion that:

     1. The Trust is a business trust with transferable shares, organized in
compliance with the requirements of The Commonwealth of Massachusetts, and the
Trust Agreement is legal and valid.

     2. The Shares to be issued as described in the Registration Statement,
including any Exhibits thereto, have been duly authorized and, assuming receipt
of the consideration to be paid therefor, upon delivery as provided in the
Agreement, will be validly issued, fully paid and nonassessable (except for the
potential liability of shareholders described in the Trust's current Prospectus
under the caption "Additional Information").

     We understand that you will rely on this opinion solely in connection with
your opinion to be filed with the Securities and Exchange Commission as an
Exhibit to the Registration Statement. We hereby consent to such use of this
opinion and we also consent to the filing of said opinion with the Securities
and Exchange Commission. In so consenting, we do not thereby admit to be within
the category of persons whose consent is required under Section 7 of the
Securities Act of 1933, as amended, or the rules and regulations of the
Securities and Exchange Commission thereunder.



                                        Very truly yours,




                                        LANE ALTMAN & OWENS LLP

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