recommendations for studying modal logic

Question

I'll be reading a textbook on modal logic with my colleagues this winter (for 3-5 months).

I might need to teach them many points from the textbook because I have a basic understanding of undergraduate mathematics and computation, whereas they don't have as much background.

Of course, we all share a common background in analytic philosophy and the essential metatheorems of classical/intuitionistic logic.

Currently, I'm considering the following three books:

1. Hughes and Cresswell, A New Introduction to Modal Logic.

2. Chellas, Modal Logic: An Introduction.

3. Blackburn, de Rijkem, and Venema, Modal Logic.

The first two are classic introductions, and I have experience reading a quarter of the third book.

Is there a better textbook for this situation?

My main considerations for the choice are as follows:

1. A sufficient level of mathematical rigor,

2. (Relatively) up-to-date materials,

3. Providing references for further reading,

4. Serving as a good reference in itself.

Answer 1

I recommend the book Boxes and Diamonds from the Open Logic Project.

It's free and permissively licensed under CC BY 4.0.

I've done exercises from the first chapter or so in informal meetings at work and it went reasonably well. Not too easy or too difficult.

I don't know if the book is long enough to last for 3-5 months of study, but it might help supplement the other stuff that you choose.