I use it in the way I use any reference book: when I need to look something up and:

- It comes to my mind the reference book exists, and

- I have the impression I will find there what I need. 

With the Poser Directory, the first condition is the critical one; entirely my fault.

Thank you for the reminder. I need to look up some Antonia stuff. 

Many thanks and please keep up the good work.