Landlording by Leigh Robinson
In 1983, my husband and I were unable to sell our house when we wanted a larger house in a better neighborhood. I was 28 and inexperienced. We were lucky enough to stumble across Leigh Robinson's book. We bought the new house, kept the old house as a rental. We followed his book to the letter, kept the rental for 10 years had positive cash flow and made a bundle in appreciation.
In 2017, I am older and more experienced. I now own an apartment building and the 12th or 13th edition of Mr. Robinson's wonderful book. It is still full of practical tips, great forms and ideas and corny humor. I pulled in out recently when I needed to draft a roommate agreement to protect the LL's (mine) interests. Again, Mr. Robinson came through.
I see a lot of talk about people spending thousands on guru courses. I think this book still costs about $20. It is timeless.