It’s often difficult for non-lawyers (or really anyone who doesn’t think about contracts regularly) to fully appreciate that contracts do not necessarily cover every eventuality that could arise between the parties and, even when they do, they can be revised if both parties need to make a change.
Why is it worth making this point in a column on laws related to publishing? Because so much writers do revolves around contracts: contracts with agents and publishing houses, and perhaps also with marketing and PR firms.
As someone who has taught contract law for many years, one of the first things I always say about contracts is to bear in mind that they are basically a risk management tool—a document agreed between the parties to explain what each has agreed to do, and to predict what could go wrong and set out how those potential future problems will be handled.
So, for example, in a publishing contract, the author is agreeing to write and deliver the work described in the contract, and is agreeing to give certain rights to the publisher to publish and distribute (and sublicense etc.) the work. The publisher is agreeing to publish the work, usually within a certain period of time from receiving a satisfactory manuscript. Then there are a bunch of clauses about what might happen if something unexpected occurs for example, if either or both parties are sued with respect to the contents of the work; if a force majeure event occurs (an unforeseen event that prevents one of the parties, typically the publisher, from fulfilling its contractual obligations in a timely manner); if the work goes out of print; if the publisher goes out of business etc. If you think about it, these are all issues that may or may not arise, but the parties are trying to manage what will happen in terms of the risks if those circumstances do occur.
Because no one can see into the future, circumstances could arise that are not contemplated in the contract. One of the parties may find it is unable to fulfill one or more contractual obligations, but neither party wants to terminate the contract or sue for breach. For example, if the author is sick and needs more time to deliver the final manuscript, many publishers will prefer to update the contract to give the author extra time than to cancel the contract altogether, depending on the circumstances.
It is important to understand that, while both parties are doing their best (at least we hope they are) at the time they enter into the contract, situations could occur that would technically be grounds to terminate the contract, but the author and publisher prefer to revise their contract than to cancel everything. That’s the reality of a contract. It can be amended if both parties agree to it. This doesn’t mean that it shouldn’t be as comprehensive and accurate as possible to begin with, but it is important to appreciate that in practice deadlines get missed and situations change and as long as people work cooperatively and transparently, many of these circumstances can be handled without too much trouble.
Of course, it is also important to appreciate—and many writers already do—that even though contracts are basically a risk management tool, the parties generally do not have equal bargaining power when entering into the contract. Many debut authors without a proven sales track record will often have a lot less bargaining power than the publishing house they are dealing with. On the other hand, bestselling authors at the top of their game might have a lot more bargaining power than they did earlier in their careers. A publishing house may also be taking more risk than the author because it is investing the money in the book to begin with so it arguably has more to lose if the book does not make money or if something goes wrong, and books have to be removed from the shelves as a result of a legal claim about the contents of the book, e.g. copyright infringement.
At the end of the day, the point of this column is to make authors aware that the text of your 
publishing contract, be it your first or your forty-first book, is not likely to be the be-all and end-all of your commercial relationship with your publisher. There will likely be practical changes, which may necessitate legal updates to the contract, as a result of circumstances that were not foreseen at the time of contract or that were foreseen as a possibility but have to be dealt with in reality when they happen (like a book not doing as well as expected, the publisher getting sued over the book, a paper shortage as a result of a pandemic etc.) As an attorney myself, I’m never going to say “ignore your contract and go with the flow”, but I am going to remind people that contracts are imperfect risk management tools and parties who want to have a long term commercial relationship ultimately may have to be flexible to obtain the most effective benefits of working together.
As always, this column is not intended as formal legal advice, and if you are concerned about signing a publishing contract, or about a problem that has arisen under a contract, you should seek advice from an expert such as a literary agent or publishing attorney.