American Society for Indexing
The American Society for Indexing , based in the USA has a well-organised website with useful information for editors and authors.
The Society is affiliated with ICRIS - the International Committee of Representatives of Indexing Societies , of which there are many.
ICRIS in turn is affiliated with The Indexer , the International Journal of Indexing.
This journal is devoted to archane but practically significant details, and one its authors has won an Ig Nobel Literature Prize for a study of the word "the" . I encourage Research Cooperative members to see the "the" article!