It has been confirmed by Seven Seas that they will be releasing Kenko Cross’s Monster Girl Encyclopedia. It is set to release as a hardcover volume on September 20th and will be priced at $24.99, the book will also have uncensored and matured content. It should be noted that the Monster Girl Encyclopedia I was originally released at Comiket back in 2010 in Japan. There have also been a variety of follow ups to the hardcover doujin overtime. Now regarding the the book itself below is a summary of it which is provided by Seven Seas and quoted from ANN:
Told from the perspective of a wandering scholar of monsters, these vibrantly illustrated pages include one hundred full-color illustrations of seductively-lethal monster girls, including everything from centaurs to succubi, from mermaids to slimes, from goblins to werecats, and much, much more. In addition, the book is filled with fascinating bios and lore, and scores of tantalizing black and white illustrations.