Books like The Spook's Tale / Interception Point

April 2019: I kind of wonder about this book, because it is simultaneously a "bonus" and also the foundation for Dreadnought, Rogue, and Zero Hour. It's complicated. There isn't any information in this book that is essential to understand or enjoy the next few books. Interception Point is only briefly mentioned once in book four, and aside from it being weird it doesn't detract from the story.At the same time... it's hard for me to dismiss this book as a one-shot because this introduces (view spoiler)[Otto's first connection with Overlord (hide spoiler)]