For anyone working with scientific names of plants, this is an essential tool. It gives you the scientific name for many a common name. At family level it gives you synonymy, technical details such as systematic position and main characters, it tells you numbers of genera and main uses. At genus level, it gives you synonymy, similar details for the more important genera, numbers of species, main uses (used as copper indicator in Russia; suitable for marmalade) or interesting little snippets (often found on greenhouse floors; hollow twigs inhabited by ants) plus comments on relationships, chromosome numbers etc. This is, as it states on the title page, 'a portable dictionary of the higher plants'. It is a goldmine.
My room is filled with books on plants; this is one of the books that has to be at hand at all times. In fact, I have two copies - one at home, one at work. A great little volume.