Short answers, pulled from the story.
Three Rivers Press is the trade paperback imprint of the Crown Publishing Group, a division of Random House. It publishes original paperback titles and paperback reprints of books that first appeared in hardcover under other Crown imprints.
The name refers to the Harlem, East, and Hudson rivers that border Manhattan, anchoring the imprint to its New York location. The name also honors the three hardcover imprints, Crown, Harmony, and Clarkson Potter, whose titles originally fed the Three Rivers list.
Three Rivers Press was originally launched in 1992 as Crown Trade Paperbacks, the Crown Publishing Group's first paperback imprint. It was rebranded as Three Rivers Press in 1997.
Three Rivers Press serves as the paperback publisher for Crown Archetype and Harmony Books, a role it took on in 2010, in addition to reprinting titles from Crown, Harmony, and Clarkson Potter.
Yes. Three Rivers Press is an imprint of the Crown Publishing Group, which is itself a division of Random House.
Crown Publishing Group is the parent division, home to several hardcover imprints including Crown, Harmony, and Clarkson Potter. Three Rivers Press is the trade paperback arm of that group, handling both original paperbacks and paperback editions of books first published in hardcover.