When I speak of niche market books I am referring to books with high interest but low readership potential. Such books may be hard to publish. There is not enough profit margin for trade publishers. They may be of interest to small presses, start-ups, hybrid publishers, non-profits, wealthy benefactors, crowd-funding, or other non-traditional sources. These books are written for an audience that is often defined by the narrow topic of interest, location, or time period.
My books are often niche market books. They are non-fiction books written for a specific purpose or audience. In most cases they are not available from the usual on-line or brick-and-mortar outlets. Copyright may be held by myself as author or by a sponsoring body. Please let me know if you cannot find a source for one of my titles.