The Concept of Anxiety
All of Kierkegaard's books have either a preface, dedication, or prayer at the beginning. This book includes a lengthy introduction. "The Concept of Anxiety" was published on exactly the same date as "Prefaces", June 17, 1844. Both books deal with Hegel’s idea of mediation. Mediation is a common thread throughout Kierkegaard’s works. His work up to this point was to show that faith was being mediated by knowledge. Here he takes up the questions of sin and guilt.
The Kallikak Family
The Kallikak Family: A Study in the Heredity of Feeble-Mindedness was a 1912 book by the American psychologist and eugenicist Henry H. Goddard. The work was an extended case study of Goddard's for the inheritance of "feeble-mindedness," a general category referring to a variety of mental disabilities including intellectual disability, learning disabilities, and mental illness. Goddard concluded that a variety of mental traits were hereditary and that society should limit reproduction by people possessing these traits.