Some runners-up of if you read one book this summer (by genre).
Science-fiction: Scythe by Neal Shusterman
Historical fiction- All the Light We Cannot See by Anthony Doerr
Fantasy- Red Queen series (The third book King's Cage
was released recently!) by Victoria Aveyard
Mystery- I Hunt Killers by Barry Lyga
Romance- The Upside of Unrequited by Becky Albertalli
Non-fiction- Alexander Hamilton: The Making of America by Teri Kanefield
Sports- Ghost by Jason Reynolds
Realistic- Every Exquisite Thing by Matthew Quick
For advanced readers- Underground Railroad by Colson Whitehead
Middle grade- Pax by Sara Pennypacker