Book excerpt: It is the job of the Product Manager to drive the product lifecycle for maximum short- and long-term profitability. Unfortunately, the job doesn't come with an owner's manual. Until now. "Trees Don't Grow to the Sky" guides the reader through the stages of the product lifecycle, including examples most people are familiar with and everyone can understand. Each step of the way, the reader will come to appreciate the nature of the four unique lifecycle stages, the market forces that put the product there, as well as what to do - and what not to do - now. This is the perfect book for anyone working in Product Management, or considering it as a potential career option. "Trees don't grow to the sky" is a business adage taken from a German proverb, warning against straight-line thinking. The product, the customer, the market will not continue to grow simply because they have always grown in the past. Growth becomes Maturity; Maturity becomes Decline. The lifecycle moves forward. In business, the results we get depend on the decisions we make, and the decisions we make depend on where we are and where we want to go. Understanding product lifecycle fundamentals is essential to making good business decisions.