Grammars

An English Grammar - as a countable noun - is a book detailing the grammar of English.

In the past most grammars were prescriptive, that is they told people how to speak. These days grammars tend to be descriptive in that they describe how people speak.

When buying a grammar, don't necessarily think that it needs to be this year's model - grammar changes slowly so books written ten or twenty years ago are still valuable in helping you to understand the basics. In fact, the ICAL Grammar Guide is a perfect introduction to grammar which will give you the basics and then allow you to go further and examine grammatical items in detail.