The World: According to Graham is the 6th book in the Infinity series, but it really is more of a spin off. The only book you need to read prior to this one is The World: According to Rachel.
At the end of The World: According to Rachel, we know that Rachel is pregnant and is going to resign her position as White House chief of staff, and she has just given the news to Graham.
Rachel Early is a strong, independent woman who never had the dream of getting married and having kids, but that all changed after her whirlwind romance with Graham Jackson. Unfortunately, Graham has a political radio talk show that is controversial and raunchy, and that can be a major problem for Rachel, because of her position in politics. Now that a baby is in the picture, can they finally have their happily ever after?