Depending upon your background, interest, and experience, your need for the information offered in this book is best met by following the material in a certain way. I think that most readers will place themselves in one of the following categories: professional programmer, student, hobbyist, former Lisp user, or merely curious. No matter which category you fit, I've described what I think you can gain by reading this book. As you read through this book, you may decide that you no longer fit your original category. This is fine -- there are no strong dependencies between chapters. If you get stuck on a particular concept, the detailed Table of Contents will help you locate the information you need.
This book tells you what you need to know about Lisp in order to write good programs, and to read Lisp code in journals, magazines, or other people's programs. Beyond that, I will introduce you to some important concepts that you may not have encountered in your use of other languages, or you may find that the Lisp approach to a familiar concept gives you a new perspective on an old idea. Even if you never have occasion to use Lisp on the job, the concepts you'll learn in this book may give you a fresh insight to help solve a tough problem in your favorite language. You'll probably want to skim up through Chapter 6 to make sure you've covered the basics. Then slow down and take a closer look at what interests you in Chapter 7 through Chapter 9, Chapter 11 through Chapter 15, Chapter 17 through Chapter 21, Chapter 23, and Chapter 24; these chapters cover concepts that are either unique to, or best expressed in, the Lisp language.
Beyond all else, I hope to impress upon you the dynamic nature of Lisp program development. Lisp usually is a pleasant surprise to someone accustomed (or resigned) to the usual edit, compile, link, and debug cycle. The biggest change is compilation of functions rather than files. You can change and recompile just one function at a time, even from within the debugger. This is really handy if you've spent hours of testing to find a problem that can be easily fixed with one small change to your program. This is just one example of how the Lisp programming environment supports your programming efforts. You'll find additional examples throughout this book. Chapter 10, Chapter 16, Chapter 22, and Chapter 26 through Chapter 28 will give you an appreciation of how Lisp supports dynamic program development.
If you've learned Lisp in a typical classroom setting, you may have come to believe that the language is nothing but lists and recursion. This book will show you that Lisp has a rich assortment of data types and control structures. Lists and recursion are only the tip of the iceberg. Chapter 3 through Chapter 24 should fill in the details on the rest of Lisp. Skim the remaining chapters so you know where to look when you have access to a commercial Lisp development environment, for when you begin your first Lisp project outside of an academic setting.
Depending upon whether you're currently taking a Lisp course, or have already finished a course and want to learn what the instructor didn't have time for, this book will help your studies by teaching you an appreciation for the language and the skills you'll need for its most effective use. Appendix A lists sources of Lisp development environments. You can use the freeware versions while you're still a poor, starving student, and refer to the list again when you're gainfully employed and want to either recommend a commercial implementation of Lisp to your employer or buy one for personal use.
To me, a hobbyist is someone who pursues programming for the challenge, for the learning experience, or as a pastime. The hobbyist is largely self taught. If you fit that mold, I'll warn you now that Lisp can be very challenging, and can teach you a lot about programming.
You can go quite a long way toward learning Lisp with one of the freeware systems available for Macintosh and DOS computers. But if you have aspirations to turn your hobby into a money making venture, you need to ask yourself whether Lisp is appropriate for your anticipated product or service. If you think in terms of databases or scripts or multimedia, you'll probably be happier with a tool that directly addresses your area of interest. If you have dreams of writing the next great videogame, you've probably already discovered that you need a language that lets you program "close to the machine" -- If so, Lisp will disappoint you. But if you want to give your game characters complex interactions, or even the appearance of intelligent behavior, Lisp is a wonderful vehicle in which to design and test prototypes of these behaviors.
No matter what your interest in programming as a hobby, this book will give you the understanding you need to explore Lisp without getting bogged down in the parentheses. Read through all of the chapters, spending more time on those which interest you the most. If you have access to a Lisp development system, spend time on Chapter 10, Chapter 16, Chapter 22, and Chapter 28 through Chapter 30; these chapters will give you the background you need in order to find your way when you get lost -- you'll find this more helpful than trying to develop an encyclopedic knowledge of the language.
If you've had a prior experience with Lisp, perhaps in a college or university programming class, this book will update your knowledge. This book will teach you things that a one semester class could never cover due to time constraints. You'll also see how commercial Lisp development systems provide tools and features missing from the freeware Lisp system that your educational institution probably used.
If you've worked on (or have attempted) a Lisp project before, you may not have had the benefit of a mentor to show you how to use Lisp effectively. This book will introduce you to the skills that you need to become a successful Lisp programmer. It is important that you understand what the language does; this book, like others before it, covers that ground. But this book goes beyond other Lisp programming books to tell you why Lisp works as it does, the best way to do things in Lisp, and (perhaps most importantly) how to approach the Lisp development environment to accomplish your goals in the most effective way.
I suggest that you use this book as a reference. The detailed Table of Contents will help you find subject areas that appeal to your interests or needs.
If you have no immediate intentions of writing a Lisp program (perhaps you're a student of programming languages), this book is still a good choice. You can learn a lot about Lisp, its development environment, and its use by reading through the chapters in order and working out an occasional bit of code on paper, to check your understanding. I've tried hard to introduce the fundamentals of Lisp in a way that doesn't belabor the details of internal representation.