Shamrock Tea by Ciaran Carson
Shamrock Tea is an Irish drug that enables its users to see things not given to ordinary mortals. They can sense colours and sounds more vividly; they can penetrate the surface of paintings; they can cross time. The narrator, his cousin and a strange Belgian friend know that their lives are ruled mysteriously by the great van Eyck painting, The Arnolfini Portrait, and they have travelled in dream like moments through the painting into other times. They discover that each moment is connected to every other. But in the strange world of Shamrock Tea, no story can be straightforward. With a cast of characters that includes the gardener Ludwig Wittgenstein, this book will blow your mind.