How to have a blank even page before every chapter

Memoir has \cleartorecto and \cleartoverso to insert clear pages until the next recto (or verso) page. It also has the \clearforchapter macro to specify how you want chapters to start.

So I think what you want is provided by Memoir with

\renewcommand{\clearforchapter}{\clearpage~\thispagestyle{cleared}\cleartorecto}

I am not sure if this is the most elegant way in the world to accomplish this. But it seems to work great for my book. I used the above code, but then added this in front of each \chapter.

\checkoddpage\ifoddpage\else\newpage\mbox{}\fi

It works great, if I open my book to the start of any chapter, the chapter starts on an odd page, and there is a blank even page just before.

Still curious if there is a more elegant way to do this. Most books (but not all) I've seen do it this way, so I am sure there is a better way.

\clearpage\null\thispagestyle{empty}

The \clearpage command flushes all floats that have appeared in the input, causing them to be printed, and begins a new page. The \null command inserts something (in this case, actually nothing) on that new page, so that subsequent calls of \clearpage will not be ignored. The '\thispagestyle{empty}` command suppresses headers and footers on your new page. If, assuming the book documentclass, you subsequently begin a new chapter, like so:

\chapter{My Chapter}

Then that will begin on the next right-page. The effect is that there will always be at least an empty left-page, and possibly an additional empty right-page before that.