After you select a single object, you can add objects to the selection and deselect objects that are selected. Using a single command, you can select or deselect everything on every layer in a document. You can also hide the selection path so that you can edit a selected object while viewing it as it appears on the web or in print.
Add to a selection
Hold down Shift while clicking additional objects with the Pointer, Subselection, or Select Behind tool.
Deselect an object while leaving other objects selected
Hold down Shift while clicking the selected object.
Select everything on every layer in the document
Choose Select > Select All.
Deselect all selected objects
Choose Select > Deselect.
Hide the path selection feedback of a selected object
Select View > Edges.
Hide selected objects
Select View > Hide Selection.
Show all objects
Select View > Show All.