Although the recent House of Lord's decision in the Twinsectra case appears to have lessened the risk of a professional being found to have been dishonest when assisting a client to perpetuate a wrong against a client, there are a growing number of circumstances when a professional may incur liability. As the author shows, the line separating negligence from dishonesty is still all too easy to cross. And what, for this purpose, is dishonesty? And what is "Nelsonian" knowledge, and what are its consequences? All professional partnerships are more acutely aware of the risks of becoming liable to a third party through the actions of their clients. Solicitors, accountants, notaries and insurance brokers, bankers, tax advisors and trustees are all exposed to risk unless the dangers are understood. Furthermore, the seriousness of this risk is compounded by the fact that where there is dishonesty, the protection of a professional indemnity policy will not be available. Add to this the dangers of partners becoming vicariously liable, then there is every need for Simon Baughen's analysis of the risks. With a systematic examination of the cases the author constructs an understandable perspective of diverse and complex judicial interpretations. Knowing receipt and knowing assistance receive particular treatment, which will be welcome to all professionals and lay a good foundation to understanding this growing area of risk.