When I’m teaching new testers I use (specific chapters from) Black Box Software Testing course by Cem Kaner and James Bach. Those are great materials. However there are some topics not covered to an extent that I would like to (probably because of the specific of software we are creating in our company). For instance multi-edit heuristic and environment-specific handling tests. Maybe those topics are more in grey-box than in black-box, but for sure they are not the only topics of grey-box...