This book uses the Pascal language. I really do not see the point to begin with Pascal, who is no longer used only by rare nostalgic. C is almost universal, not much more difficult to access, but more powerful for this kind of coding to microcontrollers. For a beginner in microcontroller, I recommend the assembler or C, but not Pascal or Basic or Fortran, who have no interest that will result anyway beginner to migrate to C and force to re-learn a new syntax.
I advise you not to start directly with the C eg the timeless "Kernighan & Ritchie". It is quite within the reach of a beginner and it will save you lots of time to progress, since in any case, almost all the programs available on the Internet and at Microchip are C