An introductory book about the Squeak/Smalltalk programming system, guiding students and developers through the environment, language, tools, and the Morphic framework by means of a series of examples and exercises.
Is figure 9.1 really neccessary? I think all important information is covered by figure 9.2 ( and maybe the explanation of Indexable Collections at page 188 continious at the next page and not at the end of 2 pages further)
in the string matching section in the text there is # but in the code you do not need the \ (and is is not in the code at this page). Why is the \ in the text. If not necessary please remove it.
also in the string matching section there are two '.' after mentioning the regex package by Vassili Bykov.
In Collecting results you introduce with collect: a simpler method to create a new collection with the modified value. While reading: 'Contrast the above with the much simpler following expression:' and the following code example I had to think about you could simply give the symbol #abs as an argument to collect in this case. Maybe introduce this method too, as an even shorter (shorter not equals to simpler, but less to write :) ) way. Not strictly necessary
In my opinion: 'Generally, you should avoid using do: unless you want to send messages to each of the elements of a collection.' is formulated a bit harshly. It is about using the right tool for the right job and not avoiding methods
In the code example: 'abc' collect: [:ea | ea asciiValue] "error!" and the next 3 examples you use ea instead of each as in most of the other examples. This is just a small incosistency
when introducing detect: maybe state that it will throw an error if it does not find a result