In the Spider’s Web by Chaim Eliav and Aleph Shin by Sender Zeyv- I think they’re brilliantly written with a lot of research and info packed in (suspense novels).
Anything written by Avner Gold- yes, those “children’s” books. Guess what- they’re not only for kids. IMHO they have a deeper level- read it when you’re 12 and read it again when you’re older… two different stories. Plus, if you like history, you’ll love these.
Nachman Seltzer- excellent and talented writer (short stories and suspense novels).
1. Gateway Diaries; 2. Partners in Torah, Partners in Eternity- personal accounts from people who came back on the derech.
Anything written by Yechiel Spero