The principal difficulty encountered in the preparation of this book has been to decide where to begin and where to end. The scope of the subject is so wide that it seemed a hopeless task to try to include designs to please everybody, or to fulfil every purpose; so I haven’t tried. Most of the drawings, although not quite all, reflect my own likes and prejudices, or are included because they demonstrate how to tackle some specific problem. A few, however, reflect my dislikes, and it may possibly amuse the reader to make his own private guesses as to which these are. No prizes offered!