From a boring but more legal and scientific viewpoint -

Try the DSM-IV [the clinicans manual] - you'd be glad to know that BDSM is not considered as a psychological 'deviancy' by courts of law. *A fetish is only considered worthy of 'treatment' is that is the only way to achive sexual gratification*

My favourite example: a man who could only get aroused by the sight of paper clips but nothing else

I found this recent paper in a quite highly rated peer reviewed RAE journal by Prof. Bruce Gross - an accomplished, respected and reknowned researcher - to be of great interest: www.acfei.com/pdf/cases/PleasureOfPain.pdf

The reference list should help you located further papers of interest, if your into the more scientific understandings of BDSM.
~kiss~
Asia
xxx