The title of this book is caught and the author of this book is Margaret Peterson Haddix. The main characters of the book are Jonah and Katherine and they are sent back to Albert Einstein's time which in the book is 1903. The main conflict in this book is that Jonah and Katherine lose the elucidator to Albert’s wife Mileva.

Main conflict
So they lose the elucidator because Mileva has stolen it when they used it. So now they have to follow her around to see if they can get it back. In the story she also finds out how to use the elucidator and make Jonah and Katherine visible again. The only way to get the elucidator back is to tell her things. See if her daughter could be healed to her fullest instead of being near death.

This book  thought was really good because it had a lot of new kind of adventures and thay had to problem solve a lot. This book I would rate a 4/5 because its a graet book like the rest of the series by Margaret Haddix Peterson.