With only three exceptions, every page of text has a margin heading which highlights the main subject matter of that page. The headings are positioned in the outer margins of the book, but are set left on both the left and right hand pages. Most margin headings are two or three lines long, the first line always being level with the first line of the text. When the first trade edition appeared, these margin headings were repositioned centrally at the top of each page in a single line heading above the text, and since the chapter numbering left no room in this revised layout for those headings which had appeared on the first page of each chapter in the subscribers' edition, a number of the original margin headings were not used. These are listed in an appendix, [Margin headings on first pages of chapters]. The margin heading for the first page of Chapter XXVIII on p 143 - 'Wejh is/captured/25.I.I7' - is included to make the list of first page of chapter headings complete, although it does in fact appear on the second page of the equivalent two page chapter in the trade edition, with the subscribers' edition margin heading for the second page - 'Rather/too well/25.I.17' - being omitted.
A number of other margin headings were omitted from the trade edition - all but three from the last pages of chapters - and this occurs where a particular chapter is type-set in fewer pages in the Cape printing. These are listed in a further appendix, [Other margin headings which do not appear in the trade edition]. 'Our/personnel' from p 321, the end of Chapter LX in the subscribers' edition, is included in this list, having become merely 'PERSONNEL' in the trade edition. Not included are a few margin headings with very minor variants between the two editions - these are, however, given in a third appendix, [Margin headings with very minor variations between the subscribers' and the trade editions].
The three exceptions without margin headings, referred to at the start of this section, are: p [40], the final page of the Book of Introduction, which none the less has ten lines of text from which a subject could have been chosen; p [285], the right hand page of a double page opening bearing the Kennington cartoon 'A forced landing', around which the type has been set - it also lacks a page number and decorative initial letter in the interests of visual impact; and p 442, the last page of Chapter LXXXIII, which has twenty-seven full width lines of text, followed by nine reducing in length and centred - there are other pages set in this style, but they all have margin headings.
A few margin headings were obviously jointly conceived, to appear opposite one another on an opening, such as, p 410, 'Miss/two/10.XI.17' and, p 411, 'The Turks/miss too/10.XI.17'. In other cases the link is more prosaic and unremarkable, as in 'Our/deductions', p 318, and 'Our equipment', p 319, but many such as these have been included in the list of linked margin headings given in an appendix, [Margin headings juxtaposed for effect]. Two listed examples, however, fail on a point of style - on pp 172 and 173 the line breaks in 'Elements/ of revolt' and 'Elements of/ tactics' come in different places, while on pp 78 and 79 - 'Reasons of/the Revolt' and 'Aims of/the revolt - 'Revolt' loses its capital letter on the right hand page. Few of the listed juxtapositions survive in the trade edition.
Many margin headings include dates, with the month given in Roman capital numerals, and the remainder in Arabic. However, in the Caslon Old Face fount the figure 1 and the letter I are the same - I. Thus 3.II.I7 can appear at a quick glance to be a representation of 3rd November [rather than February] 1917. The system is partly retained in the trade edition, but the Roman figures are type-set in lower case for easier identification - 3.ii.17.
A few margin headings in the subscribers' edition contain unnecessary capitals for the initial letters of certain words - these are listed in an appendix, [Margin headings containing unnecessary capital letters].
Lawrence had decided quite early on in his printing plans that he wanted margin headings, and mentioned them in a letter to Kennington in December 1923. He had perhaps taken the idea from Morris's Kelmscott Chaucer or the Ashbee Pilgrims Progress, from which the type had been chosen.