The Rules of Parenthood is Book 3 in the Rulebook series. It's recommended to read these in order. Max and Ruby Saddlerwhite are newlyweds who seem to have it all. They have mastered the rules of love and navigated the challenges of a long-term relationship, and now they are settling happily into married life and beginning their careers. There’s just one thing Ruby wants – to start a family. And that’s something Max isn’t sure she can give her. She has learned to work through the challenges of life and love on the autism spectrum by researching her way through major obstacles, but a baby is a challenge Max might not be up for. Ruby pushes aside dreams of starting her own family when Max’s cousin Stacy gets called to active duty, leaving behind her seven-year-old son, Aiden. She needs Max and Ruby to take care of him while she’s deployed and they rise to the occasion. It’s not all play time and games, though, as Aiden struggles with separation anxiety and the rulebooks fly right out the window as Max and Ruby discover just how difficult raising a child can be. Can Max and Ruby master the rules of parenthood, or will Ruby’s dream go unfulfilled?