In the sense that the books cover the same functions and controls as do the Nikon and Sony manuals, there are obviously similarities. However, the byThom books actually explain not only what a function or control is used for, but why you might want to use it, and what things you need to know in order to get the most from it. byThom books go far beyond what Nikon and Sony supply in their user manuals. Far beyond. This is most obvious in areas like focus or exposure and setup, where the camera maker manuals don't tell you much at all about how the system is making its decisions and why that might be important to you.
Thom Hogan has been writing better instructional manuals, articles, and books for high-tech products for over 40 years, and his work has been acclaimed by many and won awards throughout that time. So much so that a few manufacturers have sought out his works and included them with their products (Microsoft and Fujifilm, for example).
