What is this book about? Please take this book as it is, a working docu­ ment. It started as an idea that has grown. It will never be correct but should be self-correcting. In the limit, if there is one, the book should approach a 'correct' state. It is not the detail, and the numbers, that matter, but the structures and the order. These structures are inherently linked with the many minds that have made Maple, the minds of perhaps the best mathematicians, certainly some of the most useful. Our environment is not separate from mathematics; mathematics is but one tool, of several, to help with understanding the environment. It is a harsh tool that requires numbers and symbolism; Maple handles the symbolism superbly; numbers need more consideration. We have included a substantial amount on reading and writing numbers, data, and dealing with floating point numbers. It is the 'devil in the detail' that continually comes back to us in working with Mathematics and Maple. It becomes 'raw' and defined. Many of the things we do have rational and logical bases, but we don't know what they are. Often, in following the code and 'talking' with an input line to Maple, the detailed way of performing a task becomes clear. But not without frustration; the task is invariably simple, though.