Thanks to links I’ve got from Robert Milkowski’s Solaris Internals blog entry, I went to the Pearson Education website and ordered myself a book on Solaris 10, which every active Solaris user or administrator should definitely read: Solaris™ Performance and Tools: DTrace and MDB Techniques for Solaris 10 and OpenSolaris.
You can order another great book – Solaris™ Internals: Solaris 10 and OpenSolaris Kernel Architecture, 2nd edition there as well.
I should mention that the prices are much lower than those of the Amazon. Also, the credit card number checking script of their website is too strict. After none of my credit cards worked, I ended up writing an email to the support team, and they have placed my order manually.
Update: here are direct links to these books on the website of Pearson Education: