Not in Love Books in Order

The Not in Love series is Ali Hazelwood’s steamiest contemporary universe, set in the overlapping worlds of biotech start ups, private equity, and complicated families. It keeps her focus on science minded characters but leans harder into erotic tension, moral gray areas, and the ways past trauma shapes adult relationships.

The first book, Not in Love, centers on Rue Siebert, a brilliant but emotionally guarded biotech engineer at Kline, a small company working on food science innovations. After a childhood marked by instability and hunger, Rue has built a carefully controlled life, pouring her energy into her job, a tiny circle of trusted friends, and a strict rule that casual hookups never turn into anything more.

Eli Killgore blows up that sense of control almost immediately. The night before his firm moves to take over Kline, he and Rue match on a dating app and nearly spend the night together. The next morning she walks into a meeting and realizes her almost hookup is the polished front man for the investment group now dissecting her company. Eli, for his part, has his own scars from academia and from Kline’s founder, and a fierce loyalty to the partners who helped him build his firm.

Their connection turns into a secret, no strings attached affair with a built in expiration date, the day one side wins the company. The book alternates between Rue’s first person narration and close third person chapters from Eli’s perspective, letting readers sit with both their desire and the very real conflict between them. Along the way, Hazelwood does not shy away from subjects like disordered eating, messy siblings, and the ethics of profit in science.

Problematic Summer Romance shifts the focus to Maya, Eli’s much younger sister, and Conor Harkness, his older business partner and close friend. Maya is a grad student still figuring out what she wants; Conor is convinced that their age gap, shared history, and business ties make any relationship too risky. When they travel to Eli and Rue’s wedding in Sicily, a week of forced proximity in a villa full of family and co workers makes that line harder and harder to hold.

Together, the books offer a world where people with sharp minds and sharp suits are still haunted by their pasts, and where love has to coexist with contracts, board votes, and public reputations. The tone is more intense and sexually explicit than Hazelwood’s earlier STEM comedies, but the emotional through line is familiar, smart people learning to be honest with themselves and with each other even when it hurts.