iBooks is a great way to create a collection of books and PDFs that you can read on the go, and since it is categorized and open to contributions you will find that it will actually grow as you own your iPhone. Though the file sizes of the e-books may not be extensive, if you are like most users then the storage space on the iPhone is scarce. If you are done with an e-Book or PDF then you will likely want to get rid of it to free up room for new content. Here is a look at how to delete books from the iPhone.
Once you have iBooks on your iPhone and have books on it, either purchased through the store or synced through iTunes from another source, then you will be able to see them listed on your bookshelf. They will be listed either in a format that allows you to see them as book icons or in the list format. Either is fine if you want to delete books from the iPhone, as the edit options remain the same.
Go to the upper left hand corner and hit the Edit button. You will then have Move and Delete buttons appear in the upper right hand corner. They will be de-activated, but when you select a book that you want to delete they will become active. Choose the book you want to delete, and when you do a blue check mark will appear in the lower right hand corner of it, or next to it in the list view. Then choose the Delete button in the upper right hand corner. It will then give you a pop up window that will ask you to confirm the delete, and if you do then the book will be removed.
If you synced the book to your iPhone from your computer through iTunes then you will want to delete it off of there also. To do this go into iTunes and then choose Books from under the Library heading in the left hand panel, which will be directly below iTunes U. Once in there you can find the book you want to delete and right click it. Choose the Delete option from the right click menu, which will be directly under Copy. It will then ask you if you want to keep the file or move it to the trash, and you need to choose to trash it so that it is removed from your computer. Remember to empty the trash on your computer.
It is important to remember that if it was a book that you purchased through the iBooks Store then it is saved on your account on iBooks. If the book cost money then you can download it again for free since it was on your account, and if you have more than one iDevice that uses iBooks you may be asked if you want to sync all the downloaded books that were on one device to the other device. These are also going to be choices you have to make when you are determining what books you want on your iPhone and what you want deleted.