To sea-side naturalists it must be a matter of great surprise that of the inhabitants of our coast towns and villages, and of the pleasure-seekers that swarm on various parts of the coast during the holiday season, so few take a real interest in the natural history of the shore. The tide flows and ebbs and the restless waves incessantly roll on the beach without arousing a thought as to the nature and cause of their movements. The beach itself teems with peculiar forms of life that are scarcely noticed except when they disturb the peace of the resting visitor. The charming vegetation of the tranquil rock-pool receives but a passing glance, and the little world of busy creatures that people it are scarcely observed; while the wonderful forms of life that inhabit the sheltered nooks of the rugged rocks between the tide-marks are almost entirely unknown except to the comparatively few students of Nature. So general is this apparent lack of interest in the things of the shore that he who delights in the study of littoral life and scenes but seldom meets with a kindred spirit while following his pursuits, even though the crowded beach of a popular resort be situated in the immediate neighbourhood of his hunting ground. The sea-side cottager is too accustomed to the shore to suppose that he has anything to learn concerning it, and this familiarity leads, if not to contempt, most certainly to a disinclination to observe closely; and the visitor from town often considers himself to be too much in need of his hard-earned rest to undertake anything that may seem to require energy of either mind or body. Let both, however, cast aside any predisposition to look upon the naturalist’s employment as arduous and toilsome, and make up their minds to look enquiringly into the living world around them, and they will soon find that they are led onward from the study of one object to another, the employment becoming more and more fascinating as they proceed. Our aim in writing the following pages is to encourage the observation of the nature and life of the sea shore; to give such assistance to the beginner as will show him where the most interesting objects are to be found, and how he should set to work to obtain them. Practical hints are also furnished to enable the reader to successfully establish and maintain a salt-water aquarium for the observation of marine life at home, and to preserve various marine objects for the purpose of forming a study-collection of the common objects of the shore. To have given a detailed description of all such objects would have been impossible in a work of this size, but a large number have been described and figured, and the broad principles of the classification of marine animals and plants have been given such prominence that, it is hoped, even the younger readers will find but little difficulty in determining the approximate positions, in the scale of life, of the various living things that come within their reach.