Finally new book from authors of the old Solaris Internals book - actually two books. One (over 1000 pages) about Kernel Architecture in Open Solaris and Solaris 10 and the other one about Solaris Performance and Tools (yep, DTrace). This time there are three authors: Richard McDougall, Jim Mauro, Brendan Gregg. Judging from the last book they wrote these two already are a must have books.
More info here.