The Missing Link in Modern Spiritualism by A. Leah Underhill examines the development and practices of the Spiritualist movement, with particular attention to the experiences and claims surrounding spirit communication and mediumship. The work contributes to the historical literature documenting the rise of modern Spiritualism and the controversies that accompanied it.

Through its discussion of spiritualist experiences, beliefs, and phenomena, the book provides a perspective on the movement's intellectual and cultural background. It is of interest to readers studying Spiritualism, psychical research, paranormal traditions, nineteenth-century religious movements, and the historical search for evidence of communication with the spirit world.