Instruct: Classify Amazon reviews into positive or negative sentiment
Query: The best kind of mind-expanding fiction.

I thought "The Truth Machine" was one of the most insightful and thought-provoking works of fiction I've come across. I'm very excited about reading Halperin's new book. Everyone I've recommended "The Truth Machine" to has been waiting for me to recommend another book as well-written and debate-inspiring. Nothing has lived up to their expectations, but I'm betting "The First Immortal" will!