Richard Speck, Born to Raise Hell
There are two major books available about Richard Speck. The more recent and easiest to find is Crime of the Century; Richard Speck and the Murder of Eight Student Nurses by Dennis L. Breo and William J. Martin. William J. Martin was the prosecutor that put Speck in jail for the rest of his life. Another book is Born to Raise Hell: The Untold Story of Richard Speck. The Man, The Crime, The Trial by Jack Altman and Marvin, Ziporyn, M.D.( Grove Press, 1967). Dr. Ziporyn interviewed Speck approximately twice a week over a period of six months before Speck's trial and was an expert witness for Speck's defense.
Jay Robert Nash has a chapter on Richard Speck in his encyclopedia Bloodletters and Badmen (M. Evans and Co, 1995).
Additional information is also available from contemporary Chicago newspapers, such as the Chicago Tribune and the Chicago Sun-Times.