I was very positively surprised by this book. It has been on my bookshelf for a couple of months and I have been slightly intimidated by it - 700 pages long, in small print, and all about the number systems. Once I started reading it, I realised how wrong I was. This book is made very palatable by a lot of tables and pictures.
Fun fact 1:
Natural human ability to perceive numbers does not exceed four. There are traces of this in many languages. To name a few examples:
(a) several Oceanic languages distinguish between nouns in the singular, the dual, the triple, the quadruple, and the plural,
(b) Roman names for the first four sons were ‘ordinary’, but next ones were named after numerals - Quintus, Sixtus, etc.
Fun fact 2:
The Latin word pecunia (money) comes from pecus, meaning ‘cattle’. Similarly, the English word ‘fee’ comes from Old English feoh meaning both ‘cattle’ and ‘property’. Those and many more names of money have been derived from livestock.