Yes the Blue book is still good. But there is not much language syntax to learn[1], you should start with using objects directly in the Squeak or Etoys environment, preferably a few Morphs. Even simpler, see these video tutorials[2]. You'll be fluent in the language in an hour. Learning the whole environment takes a few days. Even faster, do a screen sharing session with a Smalltalker like me. merik at fiberhood dot nl

[1]Terse Squeak guide http://squeak.joyful.com/LanguageNotes

[2]https://www.youtube.com/channel/UC0iwNoV7Sptxi1qqWz_R9IA