Introductions to steganography from an information-theoretic standpoint Can I get some introductory references for steganography from an information-theoretic standpoint? I recently listened to a talk on it, and the speaker said that he knew of no good introductions to the field besides a few links and papers.

Kessler, Gary C. An Overview of Steganography for the Computer Forensics Examiner. Retrieved on 02/12/2015. www.garykessler.net/library/fsc_stego.html
Hopper, N. J., Langford, J., and von Ahn, L. (2002). Provably Secure Steganography. IEEE Transactions on Computers, 58, 662 - 678.
Hundt, C., Liskiewicz, M., and Wolfel, U. (2006). Provably Secure Steganography and the Complexity of Sampling. Algorithms and Computation, 4288, 754 - 763.
Here is a brief overview and introduction to steganography:

Christian Cachin. Digital steganography. In Henk C.A. van Tilborg, editor, Encyclopedia of Cryptography and Security. Springer, 2005

Since you asked for an introduction specifically for information-theoretic approaches, you might try this paper as a starting point for more detail:

Christian Cachin. An information-theoretic model for steganography. Information and Computation, 192(1):41-56, July 2004.

If you want a coding-theoretic perspective, you might also enjoy the following papers:

Yin Wang, Pierre Moulin.  Perfectly Secure Steganography: Capacity, Error Exponents, and Code Constructions.  IEEE Transactions on Information Theory, 2008.

Pierre Moulin, Joseph A. O'Sullivan. Information-Theoretic Analysis of
Information Hiding.  IEEE Transactions on Information Theory, 2003.

I do encourage you to also take a look at computational steganography (e.g., the Hopper et al. paper you cite in your question), as many of the powerful results are in the computational security regime