The catchy title gives me the impression that this book is for serious, already reasonably knowledgeable DOS programmers. In a chatty style, the author presents material of various depths (no pun intended) for an audience that I cannot clearly demarcate.

The book is divided into three sections. The first has some information about how DOS works. This includes information about warm and cold boots; the contents, structure, and purpose of the config.sys, command.com, and autoexec.bat system files; and a little information about the DOS interface for devices, including keyboards. The chapters in this section are not complete or detailed enough for a serious user of DOS, nor are they written without jargon or with enough detail for the novice, leaving me with the impression that the author did not have a clear idea of his intended audience. This section is not thorough. It excludes the use and syntax of DOS commands, and the topics that are covered are not done thoroughly. It includes tips that the author has found helpful, some of which are probably unique to this book and may be worth its price.

The second section has an introduction to the debug facility of DOS. Debug is a low-level debugging tool that comes with DOS and allows a user to examine and modify individual memory locations, execute in step mode, and so on. The author uses debug throughout the text (even in the first section) to help explain the workings of a microprocessor. Thus this part of the book goes into the hardware structure of a microprocessor, which is important to programmers. For example, debug is used to look at registers in explaining their use and in explaining flag registers. Again, I was disappointed in the depth of the material. The covered material would not be considered sufficient for a textbook on PC architecture.

The third section makes extensive use of debug to examine in more detail how a microprocessor works, disk file organization, and programming in debug. This approach is nice if, as the author assumes, a PC is available to the reader.

Overall, the book is not about DOS 6.0 as it differs from earlier versions. It has some value in its use of debug to point out features of DOS and the PC.