Recorded in Cambridge, MA Frank wilczek Greetings Claudio, greetings friends in Chile Claudio, as you will know, time is an illusion. The Hamiltonian that evolves systems in time is just a constraint, and it is zero, so your 60th birthday should not be a cause for alarm and there are other branches of the wave function in which you are celebrating your 20th birthday or 30th, or 40th or whichever one your prefer. Even on this branch of the wave function the 60th birthday is really a cause for celebration. It is a chance to celebrate what has been achieved by this time that ite an impressive thing to contemplate Your contributions to fundamental physics are in retrospect even more remark able than they seemed at the time. Thinking about abstract problems on how you quantize constraint systems or how you deal with extended objects and generalize the Dirac quantization conditions or how you understand black holes as quantum mechanical objects. These things to which you contributed so much and focused interest on, have proved to be some of the most unlikely, yet rich and fertile fields of theoretical physics in recent decades. You have also of course founded the institute in Chile. which has been an extraor- dinary place for intellectual adventure, not only in theoretical physics but in topics that have proved to be, again, amazing choices of things to focus on Glaciology now is at the forefront of interest in the worlds problems of climate change and what we are going to do about it and understanding it and of course, understanding how the mind works is going to be the great occupation, I,m sure, of science in the later parts of the twenty-first century. Besides intellectual achievements and up other people's intellectual achievements, you have had direct effect on people's lives, family, friends, coworkers, and in future years you'll have not only of extending your own ventures, but of watching their adventures as the solution of time marches on. So you can look back with satisfaction and look ahead with anticipation. Happy Birthday! Frank wilczek 2 Department of Physics, Center for Theoretical Physics, Massachusetts Institute of Technology Cambridge MA 02139. USA. e-mail: wilczek@mitedu4 Greetings Recorded in Cambridge, MA Frank Wilczek2 Greetings Claudio, greetings friends in Chile. Claudio, as you will know, time is an illusion. The Hamiltonian that evolves systems in time is just a constraint, and it is zero, so your 60th birthday should not be a cause for alarm and there are other branches of the wave function in which you are celebrating your 20th birthday or 30th, or 40th or whichever one your prefer. Even on this branch of the wave function the 60th birthday is really a cause for celebration. It is a chance to celebrate what has been achieved by this time that is quite an impressive thing to contemplate. Your contributions to fundamental physics are in retrospect even more remark￾able than they seemed at the time. Thinking about abstract problems on how you quantize constraint systems or how you deal with extended objects and generalize the Dirac quantization conditions or how you understand black holes as quantum mechanical objects. These things to which you contributed so much and focused interest on, have proved to be some of the most unlikely, yet rich and fertile fields of theoretical physics in recent decades. You have also of course founded the institute in Chile, which has been an extraor￾dinary place for intellectual adventure, not only in theoretical physics but in topics that have proved to be, again, amazing choices of things to focus on. Glaciology now is at the forefront of interest in the world’s problems of climate change and what we are going to do about it and understanding it and of course, understanding how the mind works is going to be the great occupation, I’m sure, of science in the later parts of the twenty-first century. Besides intellectual achievements and setting up other people’s intellectual achievements, you have had direct effect on people’s lives, family, friends, coworkers, and in future years you’ll have the joy not only of extending your own adventures, but of watching their adventures as the solution of time marches on. So you can look back with satisfaction and look ahead with anticipation. Happy Birthday! Frank Wilczek 2 Department of Physics, Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA, e-mail: wilczek@mit.edu