Although it's a few decades old, this is still the best introductory biography of Julian available. Rowland Smith's Julian's Gods and Shaun Tougher's Julian the Apostate will take you further into his world as the next stage of inquiry, but this is the scene-setter. Bowersock's interpretation of Julian is frankly bizarre (I've read Julian's works, and don't recognise the man he describes from them) and Murdoch's Last Pagan is too lightweight and 'pop' (and he gives too much credence to dubious secondary authors such as Lascarotos and Voros on Julian's death). Browning, however, is level-headed and un-gimmicky, an unpatronising "good read". Read this biography together with Julian's own writings, and the experience is very rewarding.
This is not a bad book by any means. I don't want to belittle it too much. I just feel that it had the opportunity to be something more. Say what you will about Bowersock's character assassination, at least it is scholarly and in-depth. This book seems to be written for the basic reader. It tries to offer a glimpse of what life was like at the time and explain the events without getting too in-depth. It seems rather over-simplified for my tastes. Still, it works well as a biography and if you aren't looking for a scholarly work then this book should be fine. The biggest problem with this book is a lack of citations. There are no footnotes or anything to indicate where information comes from. This might not be a problem if you're only reading it for entertainment, but if you're trying to use it for a paper or a base for further research you're going to be stuck. I also don't trust books that don't list their sources. In this day and age such a thing is unacceptable. If you're looking for a popular history of Julian then I'd recommend The Last Pagan. It is better written and it includes it's sources while still being entertaining. It is also newer and easier to find.
I feel the previous reviewer (`Arch Stanton') is much too harsh on this book, basically marking it down for the lack of footnotes. I would regard this as being in many respects a virtue. It is not an `academic' book, a doctoral thesis served up in hard covers, but the author has set out to write an urbane account explaining the background and the various problems which he does most successfully. His account of Antioch and why Julian ran into difficulties there, is masterly.
The author is every bit as much a top academic as is Glen Bowersock. He was one of the most distinguished academics of his generation - a double first in Mods and Greats at Balliol followed by twenty years as a professor at Birkbeck, ending up as one of the leading Byzantinists. Academically this book is very sound and where he uses very obscure sources he tends to quote them unobtrusively in the text. This is an urbane readable account based on sound judgement, and for that reason it deserves five stars.
I totally agree with Andrew Selkirk. It is a very good book which also gives a good introduction to life in the Roman Empire during this period. It is a great starting point for further reading about Emperor Julian.