If you are interested in buying one of my manuals you might wonder which manual would suit you. I have tried to offer my advice on the manual order page, which says that if you are new to VectorWorks and want to buy the Architect manual, you are advised to buy the Essential manual as well.
If you are new to VectorWorks and you want to buy the Landscape manual, you are advised to buy the Essential manual as well.
The reason for this is that the Essential manual covers the stuff that I consider to be essential knowledge for using VectorWorks. I used to say that this manual covers the foundation knowledge that you need to build on if you want to use VectorWorks effectively.
So, to summarize, when buying one of my advanced manuals ( architect , landscape) you should also buy the Essential manual UNLESS you are sure that you know all the basic stuff (how to use layers AND classes, viewports/sheet layers, graphics etc).