I have have been reading through a copy of the 1892 death bed edition of Leaves of Grass off and on for years. I started at the beginning several times, but have ultimately decided just to pick back up where I left off no matter how many months have passed since I last picked it up. There are passages I absolutely love in there, but there are also large stretches where the seemingly endless lists make my eyes glaze over. But when I push through even some of those are amazing. There are also many things I didn't get about the poems because of lack of context.
I chose this biography of Whitman because it promised to delve into the historical context of his life as much as his life, and on that front it very much succeeded. Like Whitman's poems, sometimes it can be too much detail, but it did exactly what I needed it to. And reading this shortly after reading The Metaphysical Club gave me a lot more insight into 19th Century America than they would have done alone.
I think Whitman gets read like the Bible a lot of times. That is, it can provide a borderline ecstatic experience and it can be turned to mean whatever you want it to. I had a picture of Whitman as the 19th Century version of a progressive. The reality, as much as it can be determined from the record is much more complicated. He had many progressive impulses, but was also very conservative in other ways, even by the standard of his time. In his own words, he contained multitudes. The book helps navigate those multitudes. It emphasized how much Whitman wanted to encompass all America and how much he was disappointed that the masses were relatively uninterested in his poems. It highlighted how slick a salesman of his work he could be.
I'm currently reading the 1855 version of Leaves of Grass and already can tell a difference in the experience. I'll keep hacking away at the death bed version for the next few years, I suspect,
Highly recommended, though you'll have to have patience for a lot of detail.