I return to this image again and again, which is a little odd, because I normally avoid the inclusion of water features in my own work. This space is about more than just the lily pool, though. Its relationship to architecture, simple plant and building material palette and exquisite execution (oh, the crisp hedges) contribute to a tiny space with huge impact.
This garden is found in many books, but this particular image--which shows its best side, I think--is found in The English Garden by Ursula Buchan. The design of the space is credited to Michael Balston.