I just received the latest edition of your great magazine and read the article about Andy Frank and his hybrid car inventions [“Andy Frank and the Power of the Plug,” March/April]. I am not sure why the auto manufacturers did not vigorously accept his invention, but I am actually responding to the quote beside the pictures by Mr. Frank regarding the need to use oil (plastic) to replace wood for building material and restore our forests. The forestry profs at his University of California, Davis campus where he works would probably not agree with his theory about the need to replace renewable forest products with plastic building materials. I know I don’t agree with him. We will still need some oil for lubrication of whatever motors or engines we develop.