For Sassenach Contract teachers like myself, this book has a rather intimidating appearance. The familiar is mixed with the unfamiliar: the familiar Law Reports with their Scots counterparts, with copious references to the works of Stair and Bell; familiar technicalities such as “implied terms” and “passing of risk” with the unfamiliar “essential validity” and “enorm lesion”. In a general sense, there is always some advantage to be gained from seeing that Other People Do Things Differently, that the way we approach Contract in the south is not the only possible approach. On that basis alone, common lawyers will find good reason to read this book; but no better reason than reading any work on civilian or comparative law. The book is clear and not unduly technical. But what special reason would a common lawyer in search of new insights have to read it?

The first surprise for a common lawyer who knows nothing of civilian systems would be the title: why “Contracts” not “Contract”, and what obligations are “related” to it? This sounds like a very good approach for the development of fresh insights, but that is not the way it works out. “Related” turns out to be a red herring. Professor Walker regards “Contracts” as concerned with the voluntary assumption of legal liability; the “related” areas turn out to be cases where liability is imposed involuntarily—in other words, the whole of the rest of the law. Walker does not attempt a summary of these “related” areas in general, nor does he expand on the nature of the relation. He summarizes only one such area: the law of “obligations arising from unjust enrichment”. Walker does not tell us why he chooses this area above others.

To say that liability for unjust enrichment is “related” to contractual liability is to take us into very deep theoretical waters. Professor Birks has already written a substantial article, which is in fact rather longer than Walker’s chapter on unjust enrichment, explaining that the chapter should not be there at all—to Birks’ way of thinking, liability for unjust enrichment has no place in a book on voluntarily-assumed obligations (“Six questions in search of a subject” [1985] J.R. 227). My own view, which there is no room to substantiate here, is that the distinction between “voluntarily–” and “involuntarily–” assumed obligations is incoherent, in this context at least: much contractual liability is only “voluntarily assumed” in the trivial sense that the promisor knows that legal consequences may follow from conduct—which is of course true of many other areas of law as well. But the chance to discuss these issues is passed up by Walker.

Walker’s assumption that he is dealing with a “law of contracts” and not a “law of contract” sounds fundamental; he stresses the very different historical developments of Scots and English/Welsh law, the Scots adopting much theory from the south but nonetheless retaining the Roman attitude that the rules on contracts differ according to the subject-matter of the contract, and that there is accordingly only a limited role for “a general theory of contract”. However, from the perspective of the late 20th century it is hard to see what all the fuss is about. There never was a period when English/Welsh courts applied the same rules to all classes of contract; what happened was that the formation of contractual theory passed into the hands of men who thought in terms of broad principle, adopting an Olympian perspective from which the subject-matter of the contract appeared merely a petty detail. These Victorian Men of Principle are long dead; their would-be successors either never returned from the mud of Flanders, or returned with a very different attitude. No theorist today can present a “theory of contract” without repeated apology for the distorting effect of imposing such a broad theory on the diverse phenomena within the law of contract. Judged from that perspective, Walker is less apologetic than most, leaping straight from a discussion