This is not a C book. It deals with assembler. However as the 8051 is one of the most popular family for microcontrollers it is likely that C programmers working in the embedded field will need to know and understand the 8051 and some assembly.
Unlike many books in this field it does not use any particular development hardware. Instead it shows small example circuit diagrams of interfaces that could be adapted to use on almost any 8051 system. There are examples of keypads, LCD outputs, frequency measurement, motor control and A to D measurements.
The authors spend some time teaching the 8051 assembler and some of the useful techniques such as string manipulation, SW timing, block transfers and floating point maths. There is a full hardware project to make with full parts listing and (US) suppliers parts numbers.
There are a lot of pages of assembly listings (repeated on the disk). Whilst this is probably a lecturers course notes as a book it does not feel like it and could be used by anyone with an interest in 8051. The disk contains an assembler, a simulator, a simple monitor and all the source code. Readers can start developing without any further hardware or experimenting with S- Dec's. This book would be of interest to electronics lecturers in the UK. Whilst not perfect it is better than most of the 8051 books I have seen recently.