Formerly (and honestly still) known as the Christian Science Sunday School, this building was designed by Araldo Cossutta (who was partners with I. M. Pei) in 1971. It is considered a Brutalist building because of its use of exposed concrete, bulky massing, and when it was built.

Brutalism is generally disliked (loathed?) for being cold and inhuman and hopelessly dated, and I shared that point of view until fairly recently. However, I've been trying to learn more about it to better understand the nuanced story. 

The Reflection Hall, along with the Colonnade and Administrative buildings (all designed by Cossutta), is a bit unique among other Brutalist buildings, because it has been properly maintained and cared for. Often, because of their negative reputation, these buildings are neglected, which only perpetuates the problem. I liked this quote from this article:

"Christian Science Church Center...shows how, with proper care and stewardship, these buildings can be wonderful participants in an active urban setting."

Here are some good resources I've been enjoying:

99% Invisible Podcast—The Smell of Concrete After Rain

McMansion Hell—The Brutalism Post, Part One: Introduction

McMansion Hell—The Brutalism Post, Part Two: What Brutalism is Not

McMansion Hell—The Brutalism Three, Part Three: What is Brutalism? Act 1, Scene 1: The Young Smithsons