Kevin's terrific assessment of Mark Twain's temper includes the 
reference to Twain realizing that his daughters were afraid of him. 
That's from an 1886 letter to William Dean Howells: "Yesterday a 
thunderstroke fell on me. I found that all their lives my children have 
been afraid of me! have stood all their days in uneasy dread of my sharp 
tongue and uncertain temper."
    What seems certain is that Twain had an uncertain temper. He's in 
good company. Like many writers, he was high-strung, incredibly 
sensitive to criticism, almost manic-depressive in his approach to 
matters great and small. This is not terribly different from 
descriptions of such 19th century authors as Edgar Allan Poe, Charles 
Dickens and Robert Louis Stevenson.
     That Twain gave in to anger quickly and easily seems clear. But, as 
with most aspects of Twain, the extent and constancy of his temper is 
unclear. You look at that letter to Howells, for instance, and it's just 
the kind of melodramatic overstatement he loved to make. Is this the 
notoriously self-accusatory Twain wallowing in yet another crime blown 
all out proportion? It's hard to say, but you balance this letter 
against the many glowing accounts of his family life, and you can almost 
see Twain building a mountain of guilt from a moment of genuine 
self-awareness.
    That's the delight and deviltry of dealing with Twain. He never 
makes it easy for you -- the author-cat "raking dust" on every aspect of 
his life and personality. I'm more than ready to believe that there were 
many times his daughters actually stood in fear of his temper. I'm 
hardly ready to accept that this was "all their days." This sounds 
suspiciously to me like the Mark Twain always searching for another 
monstrous crime to claim for himself. This Mark Twain "confesses" to 
murdering Langdon, "confesses" to killing Susy, "confesses" to stealing 
Captain Isaiah Sellers' pen name.
    There is evidence that Twain let fly with angry outbursts throughout 
his adult life. Towards the end of her life, Livy chides him for the 
endless rants against the human race. How tiresome it must have got for 
everyone around him. And yet, Livy and Joe Twichell maintained a view of 
him that was more positive of the view he held of himself. For his part, 
Twain maintained long and deep friendships with a wide circle of 
friends, all of whom acknowledged his temper, and yet also saw the warm, 
deeply human fellow quick to embrace remorse, regret and guilt. If he 
could be exasperating (and I'm sure he could), he also could be 
wonderful company for long stretches of time. We have too much evidence 
on the other side to ignore this, as well. Clara, Susy and Jean each 
acknowledged his temper in different writings. Each also left behind 
glowing accounts of an adored father. I get the idea that Twain had what 
we would today call anger management issues, but I'm hardly ready to put 
him in the "Daddy Dearest" category.
    I suspect that Twain was a bit of an emotional terrorist, holding 
loved ones hostage when he wished to indulge in temperamental outbursts. 
This is, at best, anecdotal, but I've had friends and relatives like 
this, and their outbursts were a source of both family bemusement (think 
of those shirts hitting the Hartford lawn) and frustration (think of 
Livy worrying about Twain sliding into megalomania).  We laugh about 
some of the outbursts. We shake our heads about others. I'm riding on 
pure speculation here, but I often wonder if Twain didn't inspire these 
responses among friends and family members.
    And then, as I hadn't ridden the speculation train long enough, 
there's the question of how necessary anger and temper were to Twain's 
writing.  Anger and temper run all through his works, some of it 
righteous, some of it petty (consider the autobiographical dictations 
venting on long-held grudges). Indeed, anger fuels a great deal of 
Twain's writing (the pen warmed up in hell). And he often acknowledges 
his ongoing battle with temper. There's that marvelous advice about 
writing angry letters, but learning not to send them. Twain says he 
learned to let the anger run its course. It's discharge by the mere act 
of writing the overwarm letter, but then cooling down, he pigeonholes 
them and does not send the angry letter, after all.
    Temper is a constant battle for Twain, and the resulting tension 
probably resulted in some might fine art. As to the true shape of this 
turbulent psychological river, well, it's difficult to overstate the 
case for Twain's temper, because he overstates it so dramatically himself.