This is a book which I always imagined must exist but it didn't - so I wrote it. It’s not a legal reference book. Instead it's a practical guide for commercial and contracts personnel drawing on my career working for one of the world's leading defence companies negotiating contracts ranging in value from over a billion dollars to a few thousand dollars mostly with the US Government but also with prime contractors and sometimes their subcontractors. How much would you pay for 1 hour of legal advice? Or 2 hours of accounting advice? Or to attend a convention? With this book you’re getting 25 years of contracting experience for a fraction of that amount.The title tells you everything you need to know – approximately 250 FARs and DFARS are summarised and their purpose explained. Detailed guidance is then provided from two standpoints. Firstly, whether you’re a prime contractor or a lower-tier contractor, the Guide explains how you should flow down the FARs and DFARS to your subcontractors; usually with paragraph-by-paragraph guidance on how to tailor flowdown to create subcontract terms which are fair and clear.Secondly, if you’re a subcontractor, the Guide considers which FARs and DFARS your higher-tier contractor will want flow down to you (whether mandated or not); whether you should accept a flow down; and, if so, how the language should be adapted to satisfy the original intent or to reflect any commercial understandings you have with your buyer. When flowing down the FARs and DFARS many higher-tier contractors are lazy and simplistically seek to insert themselves in the role of the ‘Government’ and subcontractors into the role of the ‘contractor’. I explain how this produces ambiguous or unfair clauses, how it often gives higher-tier contractors rights they shouldn't have or don't need and the risks to subcontractors of accepting subcontracts on these terms. For many clauses therefore, the Guide provides paragraph-by-paragraph guidance on how the FAR / DFARS wording should be adapted. On several key themes, like 'Data Rights' and 'Warranty', the Guide provides detailed introductions to each topic before dealing with the specific language of the FAR or DFARS. The Guide also highlights issues or risks which catch even the largest companies out e.g. how seemingly small modifications to the ‘Changes’ or ‘Termination’ clause could leave your company exposed. Finally, the waivers and exemptions available to non-US companies are described in considerable detail.The book does not attempt to cover a small number of specialist FARs covering areas such as construction, repair of vessels or provision of mortuary services.The best contracts are those which are fair, reasonable and pragmatic. Whether you’re a Buyer or a Seller, owning this Guide will ensure you're ready to have a sensible dialogue with the other party regarding the treatment of FARs and DFARS.