To whom it may concern: I met Jeffrey Epstein half a dozen years ago. We have been in regular contact since, with many long and often in-depth discussions about a very wide range of topics, including our own specialties and professional work, but a host of others where we have shared interests. It has been a most valuable experience for me. In the area of his own direct engagements, I have learned a great deal from him about the intricacies of the global financial system, about complex technical issues that arise in the often arcane world of finance, and about specific cases in which I have a particular interest, such as the financial situation in Saudi Arabia and current economic planning and prospects there. Jeffrey invariably turns out to be a highly reliable source, with intimate knowledge and perceptive analysis, commonly going well beyond what I can find in the business press and professional journals. Turning to my own special interests in linguistics, cognitive science, and philosophy of language and mind, Jeffrey constantly raises searching questions and puts forth provocative ideas, which have repeatedly led me to rethink crucial issues.