If he has no idea of the appearance and habits of the Tanks that fought at the Canal du Nord or that pushed back the enemy at Mormal, he cannot be expected to thrill as he should over the vicissitudes of the first converted Holt Tractor. For to one who had never seen the engine of a through express the history of “Puffing Billy” would almost certainly prove insufferably tedious. The authors, therefore, propose to deal, very briefly, with the modern Tank before plunging the reader into the dark ages of 1914, where, to pursue our analogy, Watt’s kettle-lid and the “Rocket” dwell obscurely. II Every detail of Tank Corps’ training, equipment, and tactics has been modified in view of some limitation or opportunity arising from the structure of the Tank itself. Therefore, though this book is principally concerned with the development of the Tank Corps rather than with the intricate evolution of the Tanks themselves, the reader will find it necessary to have a general idea of the construction and workings of the different types of machine. It would indeed be as idle to describe the anatomy of a snail or a lobster without mention of its shell, as to endeavour to separate the story of the Tank Corps from that of its Tanks. When the War ended in November, 1918, there were, besides obsolete types which were still used for such work as carrying and the towing of supply sledges, three main types of Tank. First, the Mark V., which was 26 ft. long, 8 ft. 4 in. wide, weighed 27 tons, and had a horse-power of 150. The Male Tanks carried two 6-pounder guns, and one Hotchkiss gun. The Female carried five Hotchkiss machine-guns and no 6-pounder guns. _The Mark V. Star._--This Tank resembled the Mark V., except that it had a length of 32 ft. 6 in., and was designed for the transport of infantry and for the traversing of trenches too wide for the Mark V. Each had a normal speed of about five miles an hour, and was protected by armour up to five-eights of an inch thick. They were both so designed as to turn easily at their maximum speed, and carried attachments for use on soft ground, which increased the grip of the tracks. Each was fought by a crew consisting of a subaltern and seven men, three drivers (two of whom normally fought the Hotchkiss guns), and three gunners.