Fair warning, the War of the Roses is a very complex and dense topic to dive into. Any book you pick up worth it's salt, will have (and better have) at least two chapters dedicated to just background before you even begin to get to the foundations of the causes for the War. The WotR is easily the most defining moment in English history between the Norman invasion and the Civil War and covers decades of history, literally.
Having said that, while this is not my subject area, and I'm not terribly well read in the topic, I do have a recommendation for a book that sits astride "popular history" and "academic history". I say that, because again, this is a dense subject and no book that is worth your time would be purely "pop history".
Alison Weir's War of the Roses, does a good job of making the subject accessible to readers of history, though not to fans of "lite history." "Lite History" to me are those pulpy history paperbacks that tend to populate the military history sections of bookstores about Navy Seals, Special Forces, Nazis, and those god awful books about the Merovingians being descendants of Jesus.
While the book only has one footnote that I can recall (giving a rough estimation of price equivalencies between 14th century money and late 20th Century), it does have an extensive bibliography and helpful index. Footnoting would be helpful in knowing the sources and providing additional information (my favorite thing about footnotes!) provided, but since the book is not "academic" its overlooked. The most helpful addition to the book are simplified family trees which I promise will be useful as the overlapping and twisting mixtures of marriages, second cousins, and family offshoots played a major part in being the cause and agitator of the war, and I promise you will refer to it more than once.
While the writing style is very casual and doesn't run down various rabbit hole topics that would fascinate an academic (and confuse the casual), it is still very dense. Keeping track of the names of the players, which Houses they were loyal to, and what role they play requires close attention to be paid or you will find yourself backtracking. I myself restarted the book three or four times before I reached page 100 over the years as I easily became lost and confused. I don't fault the writer at all as this was my first book on the subject and I often found myself lost. You will still need to sit quietly and read alone; this is not a book to read on a busy cross town bus, its by no means is a summer page turner.
Weir has a background in history, but is not a formal academic. She focuses mostly on historical fictions and biographies of England's royalty from the Middle Ages through the Renaissance. You can clearly tell that she has strong familiarity with the subject, knows how to research, and is thorough in covering the topics she tries to tackle (though through out her career some have been better than others). She presents her works in a way that makes complex histories and dense materials accessible to those who want to go beyond a tv documentary familiarity but not ready to delve into the dense undergrowth of an academic book.
For a casual yet informative and quality work, I recommend Alison Weir's War of the Roses.
Just don't use it as a source for your history paper.
I'm not an expert on this topic but I was looking to get a good academic history of the War of the Roses recently. There doesn't seem to be a single definitive work, which is pretty common for this kind of subject, since there are many different aspects/events/perspectives to consider when discussing it. There are several good works on the subject. I found this review of Michael Hicks' history really useful both in what it says about that work and how it compares it to other, similar general histories. I used it as a basis for picking which history I thought emphasized the topics that interested me the most.
I found The Winter King by Thomas Penn to be a good balance to Alison weir. It is a biography of Henry VII but provides a lot f solid background to put his accession and reign in context.
Side question: Is the Conn Iggulden fictionalised series on the War of the Roses a good read? I liked the Ghengis Khan series.