Microsoft SharePoint offers a highly structured server-side object model that makes it easy to access objects that represent the various aspects of a SharePoint Web site. SPSite:  Represents a set of logically related SPWeb objects. Each SPSite object or site collection is represented within a SPSiteCollection object that consists of the collection of all site collections on the virtual server. SPWebCollection: Represents a collection of SPWeb objects. SPWeb: Represents a SharePoint Web site. SPFolder: Represents a folder on a SharePoint Web site. SPListCollection: Object that represents all the lists in the site SPList: Object that has members that are used to manage the list or access items in the list SPFieldCollection: Object that represents all the fields, or columns, in the list SPField : Object represents a field (Columns) in the list. SPListItemCollection: Object that represents all the items, or rows, in the list SPListItem:  Object represents a single row in the list

• All dll files that are required for SharePoint to function can be found in the folders ISAPI and bin at c:\Program files\Common files\Microsoft Shared\web server extensions\15\ISAPI
• The main dll file among them is Microsoft.SharePoint.dll.