This letter invites Joseph Needham to give a lecture at the Natural Science History Research Centre at Beijing Normal University. Includes two copies of a photograph of Joseph Needham, Lu Gwei-Djen and members of the University standing behind a table, taken when they met for lunch. One copy is for Lu Gwei-Djen and one is for Joseph Needham. Both have the name Sun Yuezeng [孙岳赠] on the back.