There are three similes or allegories to make the nature and usefulness of Oham as clear as possible.
First. WE VISIT AN UNKNOWN TOWN
Let us suppose we decided we will visit a great city, say Paris in France. It is a town we do not know.
And we are so fond of our freedom that we do not want to be subject to a Tour-operator's guides or cicerones but we wish to move to and fro at our mind and will.
Of course, the main thing here so that our visit may be useful and pleasant is to get a good Paris Guide. We will seek among the Paris visitor's Guides in the market and we will get that we feel matches best our purposes.
In it, some hundreds of pages containing explanations, drawings, all color photos of buildings, monuments... and every kind of data are under our eyes so that we have every information we need of what it is worth to visit in France's capital city, Paris.
And now... what regarding the Hebrew language?
Grammars, handbooks and dictionaries are the tourist Guide of the Hebrew Language.
There are dozens of them in the market so that everybody can/may choose at his pleasure.
Now, we are already in the middle of Paris having at hand the Paris Guide we bought and the time has come to start our visit.
Do we have all we need to get an interesting -or even a very interesting- visit to the town? Of course no.
Is there something that we missed or forgot? Certainly yes.
We missed, we forgot getting a good plan or map of the town showing its streets, squares and every kind of public roads, corners and quarters. Streets, squares and other, with their names and, ideally, with house numbering, and every kind of useful information regarding such things. Let us say, if a given street has an official name (Avenue des Platanes) but has also a popular name (Avenue Droite), we will be grateful if our Guide tells about it.
And one of the best things and at a time most helpul will be this one: our Guide tells also on public transport nets such as bus and metro nets and stations.
Because of our lacking a plan or map of the town we will be obliged to ask here and there, this or that street walker, this or that policeman, where this street is or how we can go to square X.
The time spent asking people will be very great so that all this asking-time we will not be able to apply it to really visit what is worth to.
Second. WE ARE INTERESTED AT DISCOVERING A GIVEN KIND OF TREE WITHIN A FOREST
Let us suppose we enter a forest to identify a given kind of tree. There are in the forest many tree kinds. But we are interested only in oaks, in chestnuts and in beeches.
We are ignorant of the features that externally define these different tree kinds.
Imagine now that a Guide on Trees which tells about those details that help to differentiate a given tree from all the rest. Say the leaf colour, the leaf frame, the presence of a given kind of black dots within the leaves, some spots on the trunk, a given branch system, an average hight of the tree...
With little study we would be able to distinguish and identify the oaks, the chestnuts and the beeches. Or we could state that in that forest there are no chestnuts.
Third. WE WANT TO STEP ON A RELIABLE GROUND
An iron way consisting of two iron lines that run parallel: the railway.
This is a sure way so that the vehicle does not get astray.
Certainly a train cannot have a walk into the mountain nor enjoy a stroll through a wood and will be unable to visit a monument or a museum within the town nor will it be able to take a bath in the beach.
But the train will surely reach the city it intends to go to: the iron way is a reliable means, the solid ground to not to become astray...