I ran into this post in which The Piercing Bible was described as "Required Reading" on the topic of body modification:
This entry is more geared towards apprentices and those into the “past” surrounding our body modification industry/community,etc. However this is also very much available, immensely encouraged, for those out there who are clients/consumers or just general people interested in Body Modification. I believe these to be required reading (regardless if you agree or disagree with whats written), specifically for the typical apprentice that is starting out. They should read them and then approach their instructor/teacher/mentor and spark up discussions and healthy debates regarding this stuff.
Two books were listed in the post, (one other in addition to my own). I'm honored by the company, as the other book was Shannon Larratt's Opening Up Body Modification Interviews 1995-2008.