Sent from Philadelphia. The contents of this envelope of mainly anti-McCarthy literature are:

For Abolition of the Inquisitional Committees of Congress. Pamphlet by Harvey O'Connor.
The Facts about Compulsory Military Service in other Countries. Pamphlet by the National Council Against Conscription.
I.F. Stone's Weekly, June 7, 1954, Vol. 2, no. 20. 
Reprint from International Oil Worker, July 27, 1953: "Harvey O'Connor Defies Book-Burner McCarthy".
Reprint from International Oil Worker, October 26, 1953: "Federal Grand Jury Indicts Harvey O'Connor for Contempt".
Reprint from International Oil Worker, August 10, 1953: "Senate Indicts O'Connor for Defying McCarthy", and "We Support O'Connor" (An Editorial).
Depression: Hard Facts vs. Soft Soap. Pamphlet by Joseph Morton. Pacific Publishing Foundation.
"Man and the Atom" by Max Born: Introduction only by Victor F. Weisskopf. 1957.
The Gazette and Daily, York, PA., Feb. 18, 1958: "Why I Am Sailing into the Bomb Test Area" by Albert S. Bigelow.
"Petition for Redress of Grievance" by Alexander Meiklejohn, addressed to Mr. Rayburn, U.S. House of Representatives, December 12, 1957.

"The second point to be considered is the frightful loss and disappointment you prepare for your child if, as is most probably in these days, he becomes convinced that the doctrine is founded on insufficient evidence."
Presumably a fragment of a letter.

The note is unsigned, but Christopher Farley has noted the names of the senders.

Letter is signed "A very ordinary sort of chap". He read a book review of Why I Am Not a Christian in the Sunday Times. He tells BR why he is a Christian—he finds proof of God in all the good things and that God was in Christ "reconciling the world into Himself". He recommends St. Matthew's Gospel for all the basic truths of Christianity.