The Center for Reiki Research: Including Reiki in the Hospitals 
This web site offers up-to-date information on Reiki research using an iterative process of evidence-based critique, called the Touchstone Process. Study summaries of these research articles are available on this web site, as well as a complete description of the Touchstone process. The research focus on this site provides invaluable information for consumers, Reiki practitioners, and those conducting Reiki research. The web site also includes a list of 71 hospitals where Reiki is offered as a standard part of care and a powerpoint presentation on introducing Reiki in hospitals. Membership is free, and a 193 page booklet that contains all the material on this web site is available to members.
The International Center for Reiki Training 
This website provides a variety of resources useful to both consumers and practitioners of Reiki, including articles on Reiki practice, a free online newsletter, educational resources, Reiki classes, Reiki teachers and practitioners in the U.S., and information about other resources, including The Reiki News Magazine. This magazine contains articles about Reiki education and practice and is edited by William Rand, president of the International Center for Reiki Training, who seeks to "honor all Reiki schools and lineages."
The Reiki Alliance 
This is an international organization of Reiki masters who have had years of training and who are committed to continuing Mrs. Takata's practice. The Reiki Alliance is a good way to connect with a network of well-trained, thoughtful practitioners and members are listed on the website. Even if there is not an Alliance member in your immediate vicinity, the closest one may have a student or may know an unaffiliated, credible practitioner in your area.
Reiki In Medicine 
Pamela Miles' website offers general information about Reiki practice, therapy, and training. The reference section includes popular articles on Reiki basics and on how Reiki is being used in conventional healthcare, and papers published in peer-reviewed medical journals (some foreign language translations available).
Reiki Healing Arts 
Written by seasoned Reiki masters in grounded, simple language, this website helps readers understand if and why Reiki might help them. The site offers straightforward information about Reiki practice, therapy, and training, with many articles and personal stories of how Reiki has benefited a range of people.
Reiki with Mamta 
Mamta Nanda is a Reiki practitioner who has offered treatment extensively to mothers and babies at her London clinic. Her website includes case reports drawn from her practice.
Haberly, H. (1990). Reiki: Hawayo Takata's Story. Olney, MD: Archedigm.
This is an important book that contains many stories of Reiki healings in Mrs. Takata's own words. The book also tells the story of Reiki as Mrs. Takata told it, which we have come to know was a teaching story in the indigenous tradition rather than a factual history.
Miles, P. (2006). REIKI: A Comprehensive Guide. New York, NY: Tarcher/Penguin.
The first mainstream book on Reiki includes chapters on Reiki in family life, how Reiki is being used in conventional healthcare, Reiki and science, and medical research.
Twan, A. (2005). Early Days of Reiki: Memories of Hawayo Takata. Hope, British Columbia, Canada: Morning Star Productions.
Anneli Twan has published interviews with people living in British Columbia who were trained by Hawayo Takata. The students' love of their teacher and the clarity of Takata's teachings shine through this gem of a book.
OF SPECIAL INTEREST TO PEOPLE SUFFERING CHRONIC PAIN
If you are experiencing chronic pain of any kind, you may benefit from reading these books, both of which discuss the use of Reiki as part of a comprehensive approach to healing pain:
Dillard, JN. (2002). The Chronic Pain Solution. New York, NY: Bantam.
Berger, A., deSwaan, CB. (2006). Healing Pain. Emmaus, PA: Rodale.