You will certainly uncover a lot of value in this book
If you have been following the various SIGS publications, especially JOOP and SmallTalk Report, over the last few years, then the author will probably need to introduction. He has been a regular columnist and has recently received much attention for his involvement with the Extreme Programming methodology.
'A Guide to Better SmallTalk' is a collection of Beck's articles, spanning from an OOPSLA paper in 1986 to his final SmallTalk report column in 1996. While most of the articles naturally focus on SmallTalk, you do not need more than a passing familiarity with the language to follow them. The underlying theme is usually more generally applicable and C++ or Java programmers can benefit equally from the discussions on clean code or inheritance.
Two articles that are more generally appealing and have aged particularly well are 'A Laboratory for Teaching Object Oriented Thinking' (originally an OOPSLA paper, with Ward Cunningham) and 'Think Like an Object'. The latter especially is an excellent introduction to the use of CRC cards.
Some of the articles also trace Beck's first forays into patterns. While these have been pretty much accepted into the mainstream, the articles are still well worth reading, as are his musings on refactoring of code.
If you are programming in SmallTalk, you may have been following these articles in SmallTalk Report anyway; if not, this book would be a good way of catching up. If you usually program in C++ or Java, these articles can be a good way of getting a different perspective on OO and programming (perhaps in combination with somesessions with Squeak (http://wwww.squeak.org/), a free SmallTalk implementation). You will certainly uncover a lot of value in this book, even if it is not necessarily immediately technically applicable.