if you do not have a copy of the first edition, buy this one and read it. If you already have the earlier edition re-read that.
This book updates a collection of essays (well columns from 'Communications of the ACM') that were originally written in the mid-80's. The first edition and More Programming Pearls have long been among those books that every programmer should read. They highlight the importance of understanding what you are doing and how to tailor your solutions to the needs of a problem.
If you are unfamiliar with these books you should go out and buy this latest edition and work through it. It is difficult to believe that you would not become a better programmer as result. It is hard to summarise this book in the space and time I have available but the closest I can come is in saying that there is an underlying theme to these essays that is 'you must consider the special requirements of a problem before jumping in with a solution.' Just let me give you a single example: You have a limited amount of memory, you have a file of unique numbers (i.e. each occurs only once) in a specified range and must determine if a given number is a member of that list. How would you do it? If you started to answer, you have already failed because you need to know such information as the relative size of the range of possible numbers and any limitation to memory before you even start to think further.
If you are already familiar with the first edition you have a harder choice. Much of the material has been reworked to bring it more up- to-date and considerable extra material has been added but I do not think the fundamental message nor the specifics have changed much. What Jon has done is take his original thoughts and rewrite them in terms of his extra experience and the changes that have happened in the world of computing. None-the-less the fundamentals are the same.
On balance, if you do not have a copy of the first edition, buy this one and read it. If you already have the earlier edition re-read that. Of course if you have money to spare and have already bought and read the other books I recommend here and in Overload the author deserves your support and you can always give the original to an impoverished student (who will definitely benefit even if it is not the latest text).