The two prime requisites of good binding for libraries are neatness and solidity. It is pleasant to note the steady improvement in American bindings of late years. As the old style of "Half cloth boards," of half a century ago, with paper titles pasted on the backs, has given way to the neat, embossed, full muslin gilt, so the clumsy and homely sheep-skin binding has been supplanted by the half-roan or morocco, with marble or muslin sides. Few books are issued, however, either here or abroad, in what may be called permanent bindings. The cheapness demanded by buyers of popular books forbids this, while it leaves to the taste and fancy of every one the selection of the "library style" in which he will have his collection permanently dressed. What is the best style of binding for a select or a public library? is a question often discussed, with wide discrepancies of opinion. The so universally prevalent cloth binding is too flimsy for books subjected to much use--as most volumes in public collections and many in private libraries are likely to be. The choice of the more substantial bindings lies between calf and morocco, and between half or full bindings of either. For nearly all books, half binding, if well executed, and with cloth sides, is quite as elegant, and very nearly as solid and lasting as full leather; for if a book is so worn as to need rebinding, it is generally in a part where the full binding wears out quite as fast as the other. That is, it gets worn at the hinges and on the back, whether full or half-bound. The exceptions are the heavy dictionaries, encyclopaedias, and other works of reference, which are subjected to much wear and tear at the sides, as well as at the back and corners. Full leather is much more expensive than half binding, though not doubly so. Every librarian or book collector should understand something of book-binding and its terms, so that he may be able to give clear directions as to every item involved in binding, repairing, or re-lettering, and to detect imperfect or slighted work. The qualities that we always expect to find in a well-bound book are solidity, flexibility, and elegance. Special examination should be directed toward each of these points in revising any lot of books returned from a binder. Look at each book with regard to:-- 1. Flexibility in opening. 2. Evenness of the cover, which should lie flat and smooth--each edge being just parallel with the others throughout. 3. Compactness--see that the volumes are thoroughly pressed--solid, and not loose or spongy. 4. Correct and even lettering of titles, and other tooling. 5. Good wide margins.