Amos Ilgenfritz runs a robotics company. It is profitable. It is growing. In the first book, it nearly runs out of cash. Over four novels, Amos and his team face every version of that same problem: unpaid invoices, shrinking margins, and a working capital trap tightening one sensible decision at a time.
Each book stands on its own. Together, they teach the whole discipline of cash. And they all come back to the same truth.
A business does not live on profit. It lives on cash.