Last week I recorded an episode of Late Night Cocoa with Scotty in which I discuss DTrace (why it was created & how it works) and reveal the origin of the name "Cocoa Samurai", you can listen to it here: http://www.mac-developer-network.com/podcasts/lnc/lnc038/ I realize listing to my conversation I left 1 big thing hanging. Mainly I mentioned that it'd be great if the OmniGroup had DTrace probes in their apps (they do, not USDT's as far as I know, just standard ones) and if I could trace that, what I meant is that its great from a pro-user/consumer perspective if say OmniFocus acts up on me one day and I can use DTrace to trace OmniFocus and give them tracing information to help them fix the bug, I am against using ptrace() on an app because it stops me from helping you debug your apps with DTrace, especially when it's not too much trouble for me to gather this information and send it to you to help you. Also for those of you asking... Yes I am considering writing a DTrace/Cocoa book to give this subject the justice is deserves. I've got some ideas, and as soon as I get settled into my last school term (for real this time) I'll think about this in more detail, but for the moment I am fairly busy.