The Paycheck Protection Program (PPP) kicked off on April 3rd, so we’re more than a month into it now.

PPP lenders have approved more than $500 billion to 4 million different companies, including many of yours. And there still seems to be plenty of funding available for those who waited.

The legal and public-perception goal posts on this program have already moved a few times, and that will likely continue for years. Your loan may be forgiven, but it may not. The loan may also bring unwanted future “bonuses” like audits, press or lawsuits. For those who took the money: I think that was wise given what we know now. Here’s a helpful primer called You Received a PPP Loan: What’s Next? The headline is that you’ll want to track those PPP funds carefully, so you can react to changing winds if needed.

Here are a few books that look back on impacts and changing perceptions from the Great Recession from different angles: