I am literally a reading addict so I can’t decide on just one favourite book, but here are some that I find AMAZING:
The Catcher in the Rye by J. D. Salinger
A Discovery of Witches by Deborah Harkness
A Court of Thorns and Roses by Sarah J. Maas
Everything Everything by Nicola Yoon
A Minute to Midnight by David Baldacci (and its sequel)
The Book Thief by Markus Zusak
Sister and Afterwards by Rosamund Lupton
Splintered by A.G. Howard
Hopeless by Colleen Hoover
The Lie by C.L. Taylor