Any of Janet Evanovich's books that have a number in the title are good choices if you enjoy zany mysteries with some romance tossed in. The heroine of these novels is Stephanie Plum. She is a Bond Enforcement Agent whose attempts at apprehending fugitives often result in blown up cars and other mishaps. Her cohort Lulu is equally inept and her dialogue is quite entertaining. Stephanie's romantic interests Ranger, bounty hunter extradinaiar, and Joe Morelli, vice cop, add spice to these mysteries. Because of the language and situations these books would be best suited for older audiences.

Maisie Dobbs is an amazing detective in her own right. Jacqueline Winspear's heroine is full of intelligence and courage. There is a distinct history that we have only begun to learn of. Maisie is haunted by her past, but is shaking things up as a sleuth in England just after WWI.