Sage advice to overcome Mac maladies

Can I link to other iBooks from mine?

Yes. To do so, you’ll need to create a link to the book’s asset ID, which is given as the ID number in the web address of the book’s iTunes Preview page. The link is of the format ibooks://assetid/ 000000000, and you replace the zeroes with the asset ID. Full details are at bit.ly/ibklink.

How do I clear cached information in Safari for Mac?

As a first step, you may want to go to Safari > Preferences > Privacy and click Remove All Website Data. Note that sites will require you to sign in again afterwards. In the Advanced tab, turn on Safari’s Develop menu to gain access to the Develop > Empty Caches command.