If You're Reading This, It's Too Late is the second book in the Secret Series. It is based on the sense of hearing, and the "artifact" in it is the Sound Prism.
If You're Reading This, It's Too Late is the sequel to The Name of this Book is Secret in the Secret Series by Pseudonymous Bosch. It was released in October 2008 and features the same characters as the first book. The sequel to this book, and the third book in the Secret Series, This Book Is Not Good for You, came out on September 1, 2009 to Amazon customers and August 31, 2009 to consumers that visited Barnes and Noble that day. The Barnes and Noble version came with an exclusive card telling you a number to call to find clues to the identity of Pseudonymous Bosch.
For 500 years, the secret society of the Midnight Sun has been waiting for the homunculus, the man-made man, to rise, and now the evil Dr. L and Ms. Mauvais are going to throw Cass and Max-Ernest to the sharks unless they tell them where he resides. After going on an excursion with their science teacher, the two are tricked by Dr. L after receiving a note from Pietro saying he will meet them on a ship, from which they barely escape. After finding out their teacher is really Owen, the accent changing member of the Terces Society, they are introduced to the great magician himself, Pietro, who gives them a mission: find the homunculus before the Midnight Sun does. Max-Ernest also finds out that 'Terces' is "secret" backwards. Cass is grounded when she returns home, because she was missing for too long. While on the Midnight Sun ship, Cass and Max-Ernest discover a strange ball, which enables her to hear all types of sounds by putting it to her ear and makes wonderful music when held carefully. Cass also discovers a birth certificate. The name is unrecognizable, thus making Cass wonder if she was the wrong girl the Terces Society wanted. She ignores it, even though it pains her, and continues her mission.
This time teaming up with a new classmate named Yo-Yoji as well as Max-Ernest, the three need to escape the grasp of their parents, and find the alchemist's grave... but Dr. L and Ms. Mauvais have other plans.