+100 for his book. TIL he created TCL also. The book is excellent and one of the very resources that talks about architecture independent of language or tech-stack used.
Like Lamport, who is more widely known for (what was originally) his side project LaTeX than for his seminal distributed systems research including Paxos, Ousterhout tends to be more widely known by name for (what was originally) his side project Tcl than for his seminal distributed systems research including Raft.
What an amusing coincidence, I didn't know Lamport wrote LaTeX, rather I knew of him only in connection with Lamport clocks.
"(La)Tex" is believed to expand to "(Lamport)TeX" although I haven't seen an official source for that trivia :-)
Ousterhout also I think had outsized presence in early VLSI tooling, which is why TCL happened and why is it still common in tooling (pun intended)