I picked this little book up as a souvenir on a visit to the Missouri Botanical Gardens in the early 1970's as a teen and it has been a wonderful treasure.
Originally published in 1899, the information is still fresh today even though some nomenclature has obviously been updated.
The key is well constructed and this book is helpful for all levels of expertise. The beginner will find useful information as well as the expert. The charming manner in which it is written adds to the appeal of this book over 100 years later.
It was probably my first 'serious' purchase of any form of botanical reference and has served me well over the years.
Chances are, a used copy will be the only choice available, but if you run across one, be sure and take it home.