You can use the area above to navigate to all the Tools and Panels pages that are listed in this section. Click on the tool or panel icon or click on a name in the alphabetical lists.
The Tools panel layout contains 72 separate tools. Double-clicking any tool will automatically display the Tool options panel (if it happens to be hidden) and from there you can select individual options for that tool.
Many of the tools you see listed in the tools panel have a small triangle in the bottom right corner of the tool icon, which indicates that there are extra tools nested in a tool group. If you click on a tool icon and keep the mouse held down, this will reveal all the nested tools and you can click on any of the tools in this nested group to make it the new default tool for the group.
You will notice that each tool or set of tools has an associated keyboard shortcut. This is displayed whenever you mouse down to reveal the nested tools or hover with the cursor to reveal the tool tip info, and you can use these to quickly select a tool without having to always use the tools panel to select the tool you wish to use. For example, pressing on the keyboard will activate the crop tool and pressing will select whichever of the healing brush group of tools is currently selected in the tools palette. Where more than one tool shares the same keyboard shortcut, you can cycle through these other tools by holding down the Shift key as you press the keyboard shortcut. But if you prefer to restore the old behavior whereby repeated pressing of the key would cycle the tool selection, go to the Photoshop menu, select Preferences General and deselect the Use Shift Key for Tool Switch option (personally, I prefer using the shift key method). You can also Option/Alt-click the tool icon in the Tools palette to cycle through the grouped tools.
In Photoshop there is now spring-loaded tool behavior where if you hold down a key on the keyboard, you can quickly access an alternative tool. Release the key to return to the tool you are currently working with.
There are specific situations when Photoshop will not allow you to use certain tools and display a prohibit sign (). For example, you might be editing an image in 32-bit mode where only some tools can be used to edit the image. Clicking once in the image document window will call up a dialog explaining the exact reason why you cannot access or use a particular tool.