The last thing that an explorer arrives at is a complete map that will
cover the whole ground he has travelled, but for those who come after him
and would profit by and extend his knowledge his map is the first thing
with which they will begin. So it is with strategy. Before we start upon
its study we seek a chart which will show us at a glance what exactly is
the ground we have to cover and what are the leading features which
determine its form and general characteristics. Such a chart a "theory of
war" alone can provide. It is for this reason that in the study of war we
must get our theory clear before we can venture in search of practical
conclusions. So great is the complexity of war that without such a guide we
are sure to go astray amidst the bewildering multiplicity of tracks and
obstacles that meet us at every step. If for continental strategy its value
has been proved abundantly, then for maritime strategy, where the
conditions are far more complex, the need of it is even greater.

By maritime strategy we mean the principles which govern a war in which the
sea is a substantial factor. Naval strategy is but that part of it which
determines the movements of the fleet when maritime strategy has determined
what part the fleet must play in relation to the action of the land forces;
for it scarcely needs saying that it is almost impossible that a war can be
decided by naval action alone. Unaided, naval pressure can only work by a
process of exhaustion. Its effects must always be slow, and so galling both
to our own commercial community and to neutrals, that the tendency is
always to accept terms of peace that are far from conclusive. For a firm
decision a quicker and more drastic form of pressure is required. Since men
live upon the land and not upon the sea, great issues between nations at
war have always been decided--except in the rarest cases--either by what
your army can do against your enemy's territory and national life or else
by the fear of what the fleet makes it possible for your army to do.