The Amidah
Chapters 4 and 5 discuss the main prayer known as the Shemoneh Esrei (literally "eighteen"), Amidah (literally "standing"), or just Tefillah. It originally consisted of eighteen blessings with one later being added by Rabban Gamliel. It is recited three times a day while standing and interruption is forbidden.
Read more about this topic: Berakhot (Talmud)