But, like the records left by the plants themselves, most of this literature is unreadable by any but specialists, and its really vital interest is enclosed in a petrifying medium of technicalities. It is to give their results in a more accessible form that the present volume has been written. The actual plants that lived and died long ago have left either no trace of their form and character, or but imperfect fragments of some of their parts embedded in hard rock and often hidden deep in the earth. That such difficulties lie in our way should not discourage us from attempting to learn all the fossils can teach. Many an old manuscript which is torn and partly destroyed bears a record, the fragments of which are more interesting and important than a tale told by a complete new book. The very difficulty of the subject of fossil botany is in itself an incentive to study, and the obstacles to be surmounted before a view of the ancient plants can be seen increase the fascination of the journey. The world of to-day has been nearly explored; but the world, or rather the innumerable world-phases of the past, lie before us practically unknown, bewilderingly enticing in their mystery. These untrodden regions are revealed to us only by the fossils lying scattered through the rocks at our feet, which give us the clues to guide us along an adventurous path. Fables of flying dragons and wondrous sea monsters have been shown by the students of animal fossils to be no more marvellous than were the actual creatures which once inhabited the globe; and among the plants such wonderful monsters have their parallels in the floras of the past. The trees which are living to-day are very recent in comparison with the ancestors of the families of lowlier plants, and most of the modern forest trees have usurped a position which once belonged to the monster members of such families as the Lycopods and Equisetums, which are now humble and dwindling. An ancient giant of the past is seen in the frontispiece, and the great girth of its stem offers a striking contrast to the feeble trailing branches of its living relatives, the Club-mosses. As we follow their histories we shall see how family after family has risen to dominate the forest, and has in its turn given place to a succeeding group. Some of the families that flourished long since have living descendants of dwarfed and puny growth, others have died out completely, so that their very existence would have been unsuspected had it not been revealed by their broken fragments entombed in the rocks.