Michael Spence is a Fellow and Tutor in Law of St Catherine's College, Oxford.

This well-written book deserves a wide readership. I would recommend it to all those involved in the practice or teaching of the law of obligations and also to legal taxonomists. To the legal practicioner in search of the most appropriate authority to support a particular aspect of equitable estoppel, the rich source of cases in the footnotes (including unreported Australian decisions) is a bonus. D Y K Fung Journal of Contract Law July 2001 One can only admire this book's brevity, clarity, and purpose... This provocative book will no doubt be the subject of much discussion. J.E. Penner The Conveyancer and Property Lawyer September 2002

• Part 1 The duty to ensure the reliability of induced assumptions: the duty to ensure the reliability of induced assumptions - the justification of they duty, distinguishing the duty from the duty to keep promises and the duty not to lie; sketching a map of the law in relation to induced assumptions. Part 2 The emergent doctrine of equitable estoppel: introduction - methodology, the Spencer Bower and Turner categories of estoppel, the facts of "Waltons" and "Verwayen"; the elements of equitable estoppel - equitable estoppel is a single doctrine of common law and equity, able to be used as either a cause of action or defence, between two parties not necessarily in any kind of pre-existing relationship, to establish an estoppel one part, A, (or his privy?), must show that he has held an assumption, regarding the present of the future, fact or law, and that he has acted or refrained from acting, in reliance upon that assumption, to his detriment, A must also show that the other party, B, (or his privy?, induced the relevant assumption, and that, having regard to a number of specified considerations, it would be unconscionable for B not to remedy the detriment hat A has suffered by relying upon the assumption, when these things are established, the court may award a remedy sufficient to reverse the detriment that A has shown, defences. Part 3 The utility of equitable estoppel: introduction - equitable estoppel and contract, introducing the four problem areas; work undertaken in anticipation of a contract that does not materialise - contract and work undertaken in anticipation of contract, tort and work undertaken in anticipation of contract, restitution and work undertaken in anticipation of contract, equitable estoppel and work undertaken in anticipation of contract; the "battle of forms" - contract and the "battle of forms", tort and the "battle of forms", restitution and the "battle of forms", equitable estoppel and the "battle of forms"; firm offers in the construction industry - contract and the firm offer problem, equitable estoppel and the firm offer problem; variations of contract unsupported by consideration - contract and variations unsupported by consideration, equitable estoppel and variations unsupported by consideration. Part 4 Epilogue.