Great minds think alike - I was about to post the same question when I noticed yours. (That, and I think it looks on Apress' site that the cover says 3.5, though the one on Amazon doesn't have a version on it.) I'd be interested to know if it's the latest version, given the date of publication.
Theodore Jonathan Casser
SCJP/SCSNI/SCBCD/SCWCD/SCDJWS/SCMAD/SCEA/MCTS/MCPD... and so many more letters than you can shake a stick at!