Betty- Go to the website www.familysearch.org. Click on Library. Then click Find a Family History Center. You will be asked for info to pinpoint the FHC closest to where you live. You can then order relevant microfilms (to rent at $3.25 a film) through your nearest FHC, where you will be able to view them. Directories for the City of Detroit were published annually during the 1920's, the decade you asked about. Good luck with your research. Barbara