It's a little tough from the title to guess what this book will contains - Enterprise Development can a phrase loaded with various connotations for different people. What you actually get is a complete reference for running effective and efficient web development using PHP, whether as part of a major corporation or a three man web team.
Those making the case for PHP in their organisation might be interested in the first section, which covers the history and strengths of the language, but the real meat comes after, where the author lays out step by step how to build a team, gather requirements, then plan and execute a project. The scope is wide, covering tools, security, optimisation, deployment, testing and more. There's even chapters on handling operational issues and ongoing maintenance, and the book finishes with a discussion of different development methodologies, and a brief look at project management.
The tone of the writing is lively and conversational, and it's readable as a reference or cover-to-cover. However, given the range of issues featured it's inevitable that the treatment of some is light, and the author often directs interested readers to more detailed books or sites.
The book seems best suited, and most valuable, to team leaders and those with the responsibility of organising or managing development work, rather than the rank and file developers themselves. That said, the topics can be fairly technical, so would be challenging to a pure project manager without a technical background, for example.
The guide to enterprise development is really a guide to a modern web development life cycle, and anyone who follows its recommendations can expect to have a rock solid foundation for whatever they are building.