Thomas O'Conor Sloane was an American scientist, inventor, author, editor, educator and linguist, perhaps best known for writing The Standard Electrical Dictionary and as the editor of Scientific American, from 1886 to 1896 and the first science fiction magazine, Amazing Stories, from 1929 to 1938. (source: Wikipedia)
This was a recommendation from a Canadian website devoted to slide rules. The book is actually a collection of three titles: I got a cool old slide rule (ca 1924) and this book is one of the standard texts for learning how to drive the thing. I love the old typeface, patent-style illustrations, and settings of mathematical expressions. The text is pretty clear and interesting.