i helped reat to read design the register machine language and some things like that. So it was more as the book went on, om then. That took a lot of time. And then we got to the proof reading stage. We we were not type setting it ourselves, as one does. Now, there was someone else setting at tech 80. So hal was getting all this stuff to proof read. And it was gruelling reading all these copies over and over again. One day i said to hal, wait why am i doing this? I sined own to read the book. He says, well, you know, you've contributed so much to making this book better