Answer:
   
   Numerous books have been written on the subject, see the
   [5]Antisemitism portion of the reading list. Above all else, be
   prepared. Support Jews for Judaism(r) and other counter-missionary
   organizations. Jews for Judaism(r) is a Jewish organization worldwide
   (with branches in Canada, South Africa, and soon-to-be branches in
   Australia and Israel) which opposes cults and missionary efforts
   directed at Jews. Jews for Judaism(r) is North America's only full-time
   educational, outreach and counseling organization dedicated to
   countering the multi-million dollar efforts of groups such as Jews for
   Jesus. Their offices serves as Crisis Intervention Centers to help
   those in need and promote Jewish continutity. They are not specific to
   a single movement in Judaism; they unite Jews of diverse backgrounds,
   and have earned the endorsement of a wide sectrum of Jewish community
   agencies, leaders, and rabbis. Their contact information can be found
   below:
   
    JEWS FOR JUDAISM
    
   Website: [6]http://www.jewsforjudaism.org/
     * Canada, Ontario, Toronto
       Julius Ciss & Rabbi Michael Skobac
       2795 Bathurst.
       PO Box 41032
       Toronto, Ontario, Canada M6B 4J6
       Voice: (905) 761-0040
       FAX: (905) 761-0070
       [7]toronto@jewsforjudaism.org
     * South Africa, Raedene
       Rabbi Graeme Finkelstein
       PO Box 51525
       Raedene
       South Africa
       [8]southafrica@jewsforjudaism.org
       Voice: 2711-485-4865
     * USA, California, Los Angeles
       Rabbi Bentzion Kravitz & Mark Sanders [Main Office]
       P.O.Box 351235
       Los Angeles, CA
       90035-1235
       [9]la@jewsforjudaism.org
       Voice: (310) 854-3381
       FAX: (310) 854-3662
     * USA, District of Columbia, Washington D.C.
       Scott Hillman
       [10]scott@jewsforjudaism.org
       Voice: (301) 649-5494
     * USA, Illinois, Chicago
       Voice: (630) 415-1874
       [11]chicago@jewsforjudaism.org
     * USA, Maryland, Baltimore
       Mark Powers & Scott Hillman
       P.O. Box 15059
       Baltimore, MD. 21282
       [12]baltimore@jewsforjudaism.org
       Voice: (410) 602-0276
       FAX: (410) 602-0578
     * USA, New York, New York City
       Gerald Sigal
       Voice: 212-633-2125
       Address: PO Box 117
       Forest Hills, NY 11375
       [13]newyork@jewsforjudaism.org
     * USA, Pennsylvania, Harrisburg
       Mark Powers
       Voice:(717) 233-5397
       [14]harrisburg@jewsforjudaism.org
     * USA, Pennsylvania, Philadelphia
       Voice: (215) 627-2272
       [15]philadelphia@jewsforjudaism.org
       
   In general, missionaries are closed-minded, obstinate, and illogical,
   relying upon memorization rather than reason. Debate with missionaries
   takes place on the [16]alt.messianic newsgroup, not
   soc.culture.judaism or any s.c.j newsgroup.
   
    Other Resources
    
   There are a number of other resources available. First, consult your
   local federation council, and see if they have a Task Force on
   Missionaries and Cults. Some other organizations that have a web
   presence include:
     * Torah Life and Living ([17]http://www.tll.org/). TLL also provides
       a National Anti-Cult Anti-Missionary Hotline at 1-800-572-0372 or
       1-877-ANTICULT. TLL provides anti-cult, anti-missionary exit
       counseling that helps re-expose Jews to their Jewish Heritage, and
       helps to heal families shattered by messianics, missionaries, and
       cults.
     * The Jerusalem Institute of Bible Polemics
       ([18]http://jibp.israel.net/index.html). This is an organization
       that reaches out to the Jewish Community worldwide and offers its
       expertise in dealing with the problems caused by missionaries who
       seek to win Jewish souls.
     * Yad L'achim ([19]http://www.yadlachim.org/). This organization
       offers guidance, advice, direction, and solving problems of
       Israeli citizens, young and old, who have become trapped in the
       clutches of missionaries and mystic cults.
     * The Task Force on Missionaries and Cults
       ([20]http://www.tforce.org/). The leading counter-missionary and
       cult organization in North America and is the leader in providing
       information and assistance to individuals and communities in the
       U.S., Europe, and Israel
     * Derech Emet ([21]http://www.DerechEmet.org). A group working to
       save Jews from missionaries and cults. Support is provided in both
       English and Russian.
     * Outreach Judaism ([22]http://www.outreachjudaism.org/). An
       organization dedicated to bringing Jews back from the Church.
     * Jews Not For Jesus.
       ([23]http://communities.msn.ca/JEWSNOTFORJESUS/)
       
   Lastly, the Being Jewish web page ([24]http://www.beingjewish.com)
   maintains a list of Anti-Missionary Web Sites at
   [25]http://beingjewish.com/anti-missionary-links.html. Dafna Yee also
   maintains a list of over 80 anti-missionary sites at
   [26]http://dafnayee.home.attbi.co.
   
   Note: Jews for Judaism(r) is a registered trademark of Jews for Judaism
   International, Inc.