Once more, Astragal Press has rescued an old and rare book from obscurity, allowing for the broad circulation of information previously limited to the select few who could afford access. This book, first published in 1881, was written about the use of the first standard slide rule made in the United States: a Mannheim-type slide rule made by Stephens Co., a mjor rule manufacturer. Included in Riddell’s book, aimed primarily at carpenters and joiners, is a wealth of fascinating instruction on the use of the slide rule in everything from making the calculations necessary for constructing circular porches and spiral stairways, to calculating wages owed or the cost of hauling lumber. Included, as well, are lovely plates illustrating various geometric and trigonometric calculations used in construction. As a source book, it should be of great interest and value to tool collectors, slide rule enthusiasts, and woodworkers.