Over at Project Gutenberg – which is an awesome site for free books, by the way – I found a gem from 1905:
Available of reading online, or to download to a Kindle or other ebook reader, it’s a keeper. A little thin on the subject of DE- razors for some strange reason*, but covering the straight edge well as well as touching upon the strop, the brush, the soap, and other supplies. Has some sage advice too, that has not changed in over a century, such as:
Next to the razor, the most important article of the shaving outfit is the soap. In its proper use lies the real secret of easy shaving.
If you desire a really clean shave, you must go over the face the second time.
It’s a highly enjoyable read, and I urge you to take a few minutes to grab a copy.
*) The first DE Gillettes went on sale in 1903 – so when this booklet was written they were very much the new kid on the block.