In Letter 2 (6 May 1918) BR instructed his brother to ask Evelyn Whitehead to “recommend books (especially memoirs) on French Revolution”, and reported that he was already reading “Aulard” — presumably Alphonse Aulard’s Histoire politique de la révolution française (Paris: A. Colin, 1901).

In the late 1940s, when BR was going through his archives, and in the 1950s when he was revising his Autobiography, he would occasionally annotate letters. He did this to sixteen of the Brixton letters. Links to them are gathered here for convenient access to these new texts. In the annotations to the letters they are always followed by “(BR’s note.)”  
Letter 2, note 5 happy. 
5, note 6 congratulations to G.J. 

Colette first mentioned that she and Miles were trying to start an Experimental Theatre in a letter of 24 June 1918 (BRACERS 113135), indicating that Miles would earn a tiny income from it.

On 17 July 1918 (BRACERS 75814) General George Cockerill, Director of Special Intelligence at the War Office, notified Frank Russell that constraints on BR’s freedom of movement, imposed almost two years before, had been lifted as of 11 July. Since 1 September 1916, BR had been banned under Defence of the Realm Regulation 14 from visiting any of Britain’s “prohibited areas” without the express permission of a “competent military authority”.

George Allen & Unwin Ltd., founded by Stanley Unwin in 1914, was BR’s chief British publisher, had published Principles of Social Reconstruction in 1916, and was in the process of publishing Roads to Freedom (1918) while BR was in Brixton.

Since the upper-age limit for compulsory military service had been increased to 50 in April 1918, BR was faced with the unnerving prospect of being conscripted after his release from Brixton. Early in his imprisonment he was already wondering about his “position when I emerge from here” (Letter 9).

Principia Mathematica, the monumental, three-volume work coauthored with Alfred North Whitehead and published in 1910–13, was the culmination of BR’s work on the foundations of mathematics. Conceived around 1901 as a replacement for the projected second volumes of BR’s Principles of Mathematics (1903) and of Whitehead’s Universal Algebra (1898), PM was intended to show how classical mathematics could be derived from purely logical principles.

A political and literary weekly, 1907–21, edited for its entirety by H.W. Massingham before it merged with The Athenaeum and then The New Statesman. BR regularly contributed book reviews, starting in 1907.

As part of a major reform of the English penal system, the Prison Act (1898) had created three distinct categories of confinement for offenders sentenced to two years or less (without hard labour) in a “local” prison. (A separate tripartite system of classification applied to prisoners serving longer terms of penal servitude in Britain’s “convict” prisons.) For less serious crimes, the courts were to consider the “nature of the offence” and the “antecedents” of the guilty party before deciding in which division the sentence would be served.