This guide builds on the original 'C' Here guide and it is recommended that you obtain a copy of that guide if you haven't already got a basic knowledge of C programming, or another programming language (available on Amazon in Book and Kindle form - ISBN-13: 978-1546967941 or Lulu item code 23199004). This guide should be most useful to those who are doing lower-level programming - such as working with embedded systems, micro controllers or similar architectures. Similarly, anyone with a limited knowledge of C wanting to work on things like Device Drivers for Networking and USB should also find this guide of use in describing the C language features which facilitate lower level system access. The main topics covered in this guide are Structures and Unions, Binary (raw) File I/O, Dynamic Memory Allocation, Linked Lists, Access to Bits and Bytes, Logic Operations, Modules and Makefiles, Elementary aspects of system programming