That's part of the reason I'm a compulsive used book store prowler. I love to have multiple accounts, written in multiple different eras. If you get enough different accounts and enough different opinions, you can almost begin to discern a line of truth.
Houston is so interesting because he has these high profile public periods that are quite documented, followed by periods that are nearly blank (Like his actions after the strange dissolution of his first marriage - gone Indian? gone alcoholic? gone Indian/alcoholic?).
It’s an old problem...
Some Words With A Mummy (1850) - by Edgar Allan Poe:
http://classiclit.about.com/library/bl-etexts/eapoe/bl-eapoe-some.htm
(excerpt)
“Will you be kind enough to explain,” I said, “what you mean by ‘purposely so embalmed’?”
“With great pleasure!” answered the Mummy, after surveying me leisurely through his eye-glass–for it was the first time I had ventured to address him a direct question.
“With great pleasure,” he said. “The usual duration of man’s life, in my time, was about eight hundred years. Few men died, unless by most extraordinary accident, before the age of six hundred; few lived longer than a decade of centuries; but eight were considered the natural term. After the discovery of the embalming principle, as I have already described it to you, it occurred to our philosophers that a laudable curiosity might be gratified, and, at the same time, the interests of science much advanced, by living this natural term in installments. In the case of history, indeed, experience demonstrated that something of this kind was indispensable. An historian, for example, having attained the age of five hundred, would write a book with great labor and then get himself carefully embalmed; leaving instructions to his executors pro tem., that they should cause him to be revivified after the lapse of a certain period–say five or six hundred years. Resuming existence at the expiration of this time, he would invariably find his great work converted into a species of hap-hazard note-book–that is to say, into a kind of literary arena for the conflicting guesses, riddles, and personal squabbles of whole herds of exasperated commentators. These guesses, etc., which passed under the name of annotations, or emendations, were found so completely to have enveloped, distorted, and overwhelmed the text, that the author had to go about with a lantern to discover his own book. When discovered, it was never worth the trouble of the search. After re-writing it throughout, it was regarded as the bounden duty of the historian to set himself to work immediately in correcting, from his own private knowledge and experience, the traditions of the day concerning the epoch at which he had originally lived. Now this process of re-scription and personal rectification, pursued by various individual sages from time to time, had the effect of preventing our history from degenerating into absolute fable...”