Mutual wills are a little known but very convenient route for testators who wish to ensure that their estates devolve as they wish. They give rise to legally binding obligations on the part of the testators: a breach of these obligations is considered an equitable fraud and may be relied upon by a testator, or the intended beneficiaries under the mutual will, when seeking relief. Practitioners need to take particular care when setting up mutual wills or advising on them. It is a subject deep in misconceptions, in particular on the prerequisites for establishing mutual wills. Cassidy's text seeks to dispel the many myths. To this end, each prerequisite to establishing a mutual will is considered in turn and the relevant law examined.