It is generally the first thing the binder has to do with a book. The sheets are either supplied by the binders or printer (mostly the printer); should the amateur wish to have his books in sheets, he may generally get them by asking his bookseller for them. It is necessary that they be carefully folded, for unless they are perfectly even, it is impossible that the margins (the blank space round the print) can be uniform when the book is cut. Where the margin is small, as in very small prayer books, a very great risk of cutting in the print in incurred; besides, it is rather annoying to see a book which has the folio or paging on one leaf nearly at the top, and on the next, the print touching the bottom; to remedy such an evil, the printer having done his duty by placing his margins quite true, it remains with the binder to perfect and bring the sheet into proper form by folding. The best bound book may be spoilt by having the sheets badly folded, and the binders is perfectly justified in rejecting any sheets that may be badly printed, that is, not in register. The sheets are laid upon a table with the signatures (the letters or numbers that are at the foot of the first page of each sheet when folded) facing downwards on the left hand side. A folding-stick / bone folder is held in the right hand, and the sheet is brought over from right to left, the folios being carefully placed together; if the paper is held up to the light, and is not too thick, it can be easily seen through. Holding the two together and laying them on the table the folder is drawn across e sheet, creasing the centre; then, holding the sheet down with the folder on the line to be creased, the top part is brought over and downwards till the folios or the bottom of the letterpress or print is again even. The folder is then drawn across, and so by bringing each folio together the sheet is completed. The process is extremely simple. The octavo sheet is generally folded into 4 folds, thus giving 8 leaves or 16 pages; a quarto, into 2, giving 4 leaves or 8 pages, and the sheets properly folded, will have their signatures outside at the foot of the first page. If the signature is not on the outside, one may be certain that the sheet has been wrongly folded. I say generally; at one time the water or wire mark on the paper and the number of folds gave the size of the book. There are numerous other sizes, but it is not necessary to give them all; the process of folding is in nearly all cases the same; here are however, a few of the sizes given in inches.