Have you read this book yet? No? Then read it. Just stop what you're doing and 
 read it. 
 This book. I don't even really know how to describe it. First things first: this book has diversity. The three main characters (and believe me if you read this series you will fall in love with them) are an Irish guy - Liam O'Conner - who worked on the Titanic in 1912, an American woman from 2010 - Madeline 'Maddy' Carter - and Saleena 'Sal' Vikram, a fourteen year old from India in 2026. 
 The book, as the name and blurb suggests, is about time travel. More specifically, three people who must stop time from changing 
 AT ALL COSTS. 
 But it's also about so much more than that - it's about the characters of Liam, Maddy and Sal. Their relationships with each other, their adjustment to the situation they're placed, the actions they take and the reasons behind them. 
 The story is the characters. The characters drive the plot, the characters create the setting. 
 Every book in this series has a different setting, a different goal, which leaves the only thing in the series to remain constant (besides the rules of time travel of course) are the characters. Liam, Maddy, Sal, and also the support units, who aside from being genetically engineered super humans with silicon wafer units in their heads, serve at times as comic relief while also having stories and development of their own.