What books are the best desk references for histology and immunohistochemistry?
I'm asking because I supervise a core facility for histology at a University and the participating investigators are asking me to have more recent books on hand for them to look through. Especially desirable are books that describe a wide variety of types of histochemical stains, suggest protocols for troubleshooting rare tissues/hard to cut tissues, how to optimize for immunohistochemistry signals, etc. Expect I'll need at least 5 books to cover all topics adequately.
I'll visit the library to test drive whatever suggestions you have, and make my final purchasing decisions after that.