not interrupting one another or forgetting to help play the game.
That's the difference between pictures and photographs. A photograph
is almost always wrong somewhere. Something is out of place, or
something is there which ought to be away, or the light is wrong; or,
if it's coloured, the colours are just not in keeping with one another.
If it's a landscape the trees are where we don't want them; they hide
what we want to see, or they don't hide the very thing we want hidden.
Then the clouds are in the wrong place, and a wind ruffles the water
just where we want to see something reflected. That's the way things
actually happen in the real world. But in the world of 'Let's pretend,'
in the world of art, they don't happen so. There everything happens
right, and everybody does, not so much what they should (that might
sometimes be dull), but exactly what we want them to do--which is so
very much better. That is the world of your art and my art.
Unfortunately all the pictures in the galleries weren't painted just
for you and me; but you'll find, if you look for them, plenty that
were, and the rest don't matter. Those were painted, no doubt, for
some one else. But if you could find the some one else for whom they
were painted, the some one else whose world of 'Let's pretend' was
just these pictures that don't belong to your world, and if they could
tell you about their world of 'Let's pretend,' ten to one you'd find
it just as good a world as your own, and you'd soon learn to 'pretend'
that way too.

Well, the purpose of this book is to take you into a number of worlds
of 'Let's pretend,' most of which I daresay will be new to you, and
perhaps you will find some of them quite delightful places. I'm sure
you can't help liking St. Jerome's Cell when you come to it. It's not
a bit like any room we can find anywhere in the world to-day, but
wouldn't it be joyful if we could? What a good time we could have there