The option doesn't appear on the one I want to delete. It did on others, though.
It sounds like you may be trying to delete an ideabook that was shared with you? Please shoot us an email through support.houzz.com and we can help you out. Thanks!
I just figured out how to do this! You need to click on the ideabook you want to delete, click the < ... More > top right and select 'Settings', the option to delete will appear here.
Thank you Brittany! Was attempting to do it for so long!
Click on the ideabook. In the lower left hand corner look for "Settings".
You'll see the option to delete the Ideabook.
bobparrot has the right answer. ^^ This worked.