W. van der Hoek and J.-J. Ch. Meyer, Epistemic Logic for AI and Computer Science, Cambridge University Press, paperback edition 2004, ISBN 0521602807.
(Errata of the 1995 version of the book can be found here.)
Study guide for epistemic logic part 1 and part 2.
(Here they are in PDF format: part 1 and part 2).
Logics Workbench manual by Hans van Ditmarsch:
Manual and
LWB notation.
For more, visit the LOK-web.