A good argument could be made that General Tom Green of Texas by way of Tennessee was the best cavalry commander that the Trans-Mississippi Confederacy had to offer. As far as I know, only two biographies have been published to date: Odie Faulk's General Tom Green: A Fightin' Texan (Texian Pr, 1963) and On Valor's Side: Tom Green and the Battles for Early Texas (Dogwood Pr, 1999) by Brian Sayers. Both works are frequently cited in the literature. I've never seen or read Faulk's bio but recently borrowed a copy of On Valor's Side to peruse out of curiosity.
It's a rather brief treatment of Green's life and military career, running only 190 pages (including chapter notes, illustrations, and bibliography) in a small 5.25 x 8 trade size paperback. In addition to Green's military service during the Texas Revolution, the Mexican-American War, and the Civil War, Sayers covers Green's upbringing, his marriage and home situation (which included generous mass adoption of orphaned children from his wife's family), and as his various work pursuits and political appointments. Fighting with Sam Houston's army in Texas and later with Zachary Taylor's command in Mexico, the latter described in some detail in the book, made Green a hero in his adopted state.
The book's account of Green's Civil War service is broadly inclusive, if a bit imbalanced and inconsistent in depth. While Sayers incorporated some Texas based manuscript resources into his narrative, the Civil War content is largely based on published sources. Much of the emphasis is placed on the disastrous New Mexico Campaign, leaving a relatively limited amount of page space for Green's equally significant 1863-64 operations along the Texas coast and in Louisiana. A few paragraphs are devoted to Green's most serious defeat (at Fort Butler in June 1863), but perhaps the general's greatest victory in a mostly independent role, the battle fought at Kock's/Koch's/Cox's Plantation only weeks after Ft. Butler, is surprisingly mentioned only in passing.
Sayers doesn't totally shy away from some of the more controversial aspects of Green's Civil War career, specifically his alleged heavy drinking. Several sources mention the general's affinity to alcohol, but signs seem to point toward its general limitation to off duty hours. On the other hand, it's debatable what role, if any, alcohol played in the foolhardy attack at Blair's Landing in 1864 that led to Green's death. Several accounts of his grisly demise exist but the book doesn't task itself with weighing the available evidence and offering its own interpretation of the event.
Much has been written about Green's Confederate career in the sixteen years following the publication of Sayers's biography and there really isn't anything Civil War related in On Valor's Side that hasn't been covered since and with greater focus and depth. At this point in time, it's the other parts of the book, those comprising information about the public and private aspects of Green's domestic life and civilian occupations, that have the most value to Civil War students.