I use the Calibre ebook management system. It has a reasonably good converter, and converts pdf to epub, among many others. The only problem I have is that I can't seem to enlarge the fonts, even after manually adjusting the conversion settings; and books converted in this manner do not respond to the font scaling commands on my e-reader (kobo).
(a squeak from a long-term silent reader)
how about: http://www.accesspdf.com/pdftk/
i find that when i convert to PDF using Calibre when i put it onto my sony reader PRS-300, not all the pages upload, like its blank for half of teh book, but all the pages are there when you open it on my computer??? does anyone know how to fix this??? because most of my ebooks are pdf format??
also does anyone know a free pdf to word.doc creator that converts the whole book???

I really like odf but its so annoying when the whole book doesnt show??

or i dont know if its my ereader because all other formats seem to work??

help please
Thank you for the link. It's very useful.
There are a lot of resources for editing pdf documents and for me it has been difficult to find one that doesn't require a large monthly subscription or upfront fee to download the software (I want to know what I'm getting before I commit to buying it if possible). One editor I really like is PDF Pro, https://www.pdfpro.co

With PDF Pro you can covert documents from Microsoft Word, Excel, PowerPoint, Publisher) without having to install any software, so all your documents are saved in the cloud.They also have a pay as you go service and allow you to download your first PDFs for free so you can test it out and decide if you like it.
Is there a free or cheaper program that does the same thing? $199.99 for a program is a bit steep for me at least.