This last volume of the splendidly gruesome Monstrumologist series depicts sixteen-year-old Will Henry rebelling against the authoritarian rule of his mentor and sometimes nemesis Dr. Pellinor Warthrop more than ever before. Through the last three books, Will has continued to spiral down, down, down into a personal darkness from which he believes there is no salvation. Now a stone cold teenager, Will Henry has to fight to feel anything at all, except when it comes to his childhood sweetheart Lilly Bates. When they meet again as teens, he is instantly smitten, and not pleased to be distracted from his courting by Dr. Warthropâ€™s new obsession with yet another believed-to-be-extinct monster. But Will can never forget the secret that has dwelled in his blood since the beginning, which casts a shadow on his current bond with Lilly. Soon he is embroiled in a convoluted scheme that ends up turning all his relationships to ash, including the one that has defined him his entire life: his complicated connection to Warthrop. After breaking apart in the most spectacular manner, Will and Warthrop meet one last time, each uncertain about his life and legacy and if the world is big enough to contain them both. This concluding title of the Monstrumologist epic is disappointingly thinner than itâ€™s predecessors in plot and page numbers. The beginning is a bit confusing, as it shifts forward and back in time from the events that lead to Will and Warthropâ€™s break to their final meeting. In addition, Warthropâ€™s attempts to secure his latest biologically aberrant prize initially devolves into a shaggy dog mystery that is sometimes difficult to follow. However, once yet another beloved character is killed off, the plot becomes clearer and Yancey pulls off a neat slight of hand identity trick near the end that left me both impressed and very, very relieved. And while the ending feels a little too neat, it also feels absolutely true. I am deeply sorry to see Will Henry and Dr. Warthrop go, as this is without a doubt one of my favorite book series of all time. To follow their horrific adventures from the beginning, start here, go there and there and end here when The Final Descent comes to a library, bookstore or e-reader near you.