Man has always shaved in some kind, even the Stone Age people has shaved with roughly shaped flint knifes. The proof or maybe more an interpretation can be found on Youtube, where you can find videos of people showing how to shave with a flint "razor".

But things probably first took off when mankind was able to shape metal.

The first "modern" razor is the straight razor sometimes also known as the cut throat razor. When it comes to it, you can shave with almost any kind of knife, given they are sharp enough (again; check out Youtube if you have the interest), but the straight razor is designed with that single purpose in mind.

Straight razors comes in a number of sizes, and is normally sized by the height of the blade in 8ths or 16ths of inches, for example 4/8", 6/8" or 11/16" etc.

Furthermore the shape of blade looked at from the end is mentioned and it can be from wedge shaped to a full concave shape known as Full Hollow or sometimes Double Hollow. The preferred shape is often chosen from the type of beard. Men with a thick beard often prefer a Wedge straight, while men with lighter beard often choose a Full Hollow, without this being the gospel, as all straights can give a close shave, it is more a question of personal reference regarding weight, balance and look of the razor.

Shaving with a straight razor is for me the ultimate form of shaving. As most things in life; if you know how to do it, it is not difficult, but it takes a good deal of learning to master a straight razor as you are not given anything, You are in control of all parameters of the shave: a sharp edge, the correct angle, the pressure, the proper preparation etc. etc.

Straights

needs restoration

needs restoration

needs new scales