This vaad on Tefillah was given in Yeshiva Gedolah of Greater Washington. In the first few vaadim, R' Aaron goes through some fundamental concepts of tefillah. Afterwards, he begins to go through the actual siddur (beginning with Shemonah Esrei and working his way backwards). The vaad pulls from many different sources but much of what is said can be found in R' Aaron's sefer "Tefillah L'Moshe" - A collection of the commentaries of the Rishonim on the Siddur. It is available for sale at eshelpublications.com. Please note that some of the vaadim are missing. We are trying to track them down! This vaad is no longer active. So these published vaadim are it!