How to go to most recent version and edit?

I’ve spent about three weeks trying to find the secret of returning to the most recent edit of my voice/music mix file. I must be really dumb, since this has to be a really basic function. I thought the “history” function might do it, but then found that the history is lost when the project is closed. Opening a project doesn’t seem to do anything. What am I missing?

File : Recent Files
Shows a list of the most recent files/projects.

Audacity has a virtually unlimited number of “undo’s”. However, once you close a project (or Audacity), this undo history is discarded in its entirety. In the future, you may wish to use “File > Save Project > Save Lossless Copy Of Project” frequently to make checkpoints of a long and sustained edit. For additional insight, see this forum discussion: History of effects after saving project