The rating should really be 3.5.
This is a scholarly, generally quite comprehensive account of one of the 17th century's finest and most diverse poets. Murray is good at giving detail as to how we know what we know about Marvell and explaining the problems with sources and contemporary accounts. This might be a little mind-boggling and seem pointless to the ordinary reader, however, so beware - this is definitely a book based on facts and not a gripping 'story' of Marvell's life and times.
Nevertheless, the prose is readable if dense with information and I found Murray's style likable enough.
The main problem is that this biography is a bit uneven. There are a few short investigations of his actual poetry but these are few and tend to scratch the surface so that the reader is left wondering what the point of beginning was. Occasionally poetry is used to illustrate a point about Marvell's life but this is so unevenly done that it feels messy. It may have been better to exclude any real detail on the poetry or (preferably) to write a biography more heavily engaged with the actual work of this man who was equally poet and man of his times.