I've spent the last week or two reading Julie Phillips's biography James Tiptree, Jr.: The Double Life of Alice B. Sheldon. Phillips does (as far as I can tell) a good job of covering Sheldon's life, her work, and the familial and historical context that shaped her, and that she spent her life fighting against the constraints of. I recommend it, if you're interested in Tiptree (obviously) or in feminism or the 20th-century United States. (This isn't a thorough review; several people have already published good, detailed ones.)
Background is provided, without ever feeling excessive. Phillips gives the reader a lot of information about Sheldon's family and upbringing, both Africa and upper-crust Chicago society of the time, and the relevant parts of the early days of the Women's Army Corps. There's also good material from, and about, Tiptree's correspondents within the science fiction community, including writers, editors, and fans. I was particularly interested in the bits about, and quoted correspondence from, Ursula Le Guin and Joanna Russ. I think there's enough background there for someone without the fannish connections or background to understand the interactions and the state of the genre at the time. Phillips mentions better-known national and world events that affected Alli Sheldon and her husband, Ting: the Bay of Pigs (because of his work at the CIA) and Watergate (for how she felt about it).
The author refers to her subject by several different names, and even pronouns, depending on the context: "Alice" or "Alli" (the nickname she was given by her mother-in-law and gladly adopted) or "Davey" (the married name her fellow WACs called her) or "Tip". This works, for keeping track of Sheldon's different personas, socializing, and activities, and is less awkward than referring to "Tip" as "she" would have been, I think.
Phillips's genuine sympathy for her subject shows; she doesn't gloss over the difficult bits, including Sheldon's depressions, use of (mostly doctor-prescribed) amphetamines, and long dalliance with suicide before the end, but I never got the feeling that she blamed Sheldon for them. She explores Sheldon's problems with the role of a "woman", as well as her ambivalence about organized feminism
I hadn't known how much of an effect the revelation of "Tiptree's" "real" name and gender had on her, personally or as a writer, because it was all in the past by the time I was noticing her work. "Double Life" is almost an understatement; Sheldon tried on several lives, and never really felt settled or satisfied in any of them. The Tiptree persona wasn't just useful to her as a writer; it let her make friends, by correspondence, in a way that she'd found difficult in other contexts.