The process for getting a book chapter indexed in PubMed is different from the process for a journal article. Once a journal is accepted for indexing in PubMed, all articles published in that journal are automatically indexed in PubMed. This is not the case with books. For books, there is something called NCBI/NIH/NLM Bookshelf. Each book is assessed separately. After publication, we submit all our books to Bookshelf for evaluation. If accepted after evaluation, each chapter will be indexed in PubMed. The entire process could take up to six months. After acceptance by NCBI/NIH/NLM bookshelf, to get indexed, we have to create special files in accordance with the guidelines of Bookshelf. We meet the costs associated with this, and do not charge our authors.