There are many more books by Pir Vilayat Inayat Khan, Murshid SAM and others than are listed here; this is just an initial sampling.
___________________________ Pir Vilayat Inayat Khan
The Ecstasy Beyond Knowing: A Manual of Meditation
Toward The One
___________________________ Moineddin Jablonski
A Gift of Life: Aphorisms and Poems
____________________________ Murshid SAM (Samuel Lewis)
____________________________ Wali Ali Meyer,Shabda Khan