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Note: While some republishers do not even attempt to use properly issued ISBNs, noting those that do enables circular refs to be spotted more easily.
All titles reviewed are verbatim reprints of a collection of Wikipedia articles. Some titles state that "some" of the content is in the public domain. Website states that "Each book always has the latest content available on the day of ordering. The content of all book is updated on a perpetual basis." They further state that they have "used its best efforts in collecting, analyzing and preparing data, information and materials for this unique guide." Claiming to be the publisher, they also say that use "for any commercial purposes requires a special written permission from the publisher."
Have emailed the published. And touched base with Amazon
Dear Dr. Heilman and Mr. Cohen We have received your mails concerning text in Understanding and Management of Special Child in Pediatric Dentistry.
We have taken the matter up with the editors of the book and the contributors to the chapter in question.
We take care to ensure the veracity of texts, but in this case our systems appear to have failed. However, we have decided to permanently withdraw the book from sale, and we will remove the title from our website and recall the book from our wholesalers and distributors.
Thank you for bringing this matter to my attention.
"Spiritual Value of Social Charity", in which the first visible page of text - apparently written by the publisher themselves - is a direct copy of "History and philosophy of social work in India" (published by somebody else, decades earlier).
A randomly chosen sentence from "Encyclopedic Dictionary of Sanskrit Literature" also appears in a 1996 book from a different source: 
"Nuclear weapons and national security: emerging challenges for Asia" copies extensively from 
A randomly chosen sentence from "21st Century India : View and Vision " also appears in a 2003 book from a different source: 
The first sentences of "Rāvaṇa and Laṅkā",  nominally written by R.K. Ramakrishnan, is copied from "India in the Rāmāyaṇa age: a study of the social and cultural conditions in ancient India as described in Vālmīki's Rāmāyaṇa", published 1967 
"Basics of guidance and counselling" appears to copy from a 1984 book by a different Indian publisher which in turn copies from the 1965 "Testing for Teachers".
"Role models in management (leadership and communication)" copies from "Effective Leadership" by Adair
From book descriptions on Amazon: "Hephaestus Books represents a new publishing paradigm, allowing disparate content sources to be curated into cohesive, relevant, and informative books. To date, this content has been curated from Wikipedia articles and images under Creative Commons licensing, although as Hephaestus Books continues to increase in scope and dimension, more licensed and public domain content is being added. We believe books such as this represent a new and exciting lexicon in the sharing of human knowledge."