Holmes on problem solving..............

It is a capital mistake to theorize before you have all the evidence. It biases the judgment.

In solving a problem of this sort, the grand thing is to be able to reason backward. That is a very useful accomplishment, and a very easy one, but people do not practise it much. In the everyday affairs of life it is more useful to reason forward, and so the other comes to be neglected. There are fifty who can reason synthetically for one who can reason analytically.

Eliminate all other factors, and the one which remains must be the truth.

I never guess. It is a shocking habit — destructive to the logical faculty.

You see, but you do not observe. The distinction is clear.

Education never ends Watson. It is a series of lessons with the greatest for the last.

It is quite a three pipe problem, and I beg that you won't speak to me for fifty minutes.

Life is infinitely stranger than anything which the mind of man could invent.

There is nothing more deceptive than an obvious fact.

You know my method. It is founded upon the observation of trifles.

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

Nothing clears up a case so much as stating it to another person.

There can be no question, my dear Watson, of the value of exercise before breakfast.

I'm off.  The game is afoot.

Ed. note:  Picture source here.  Choosing which Holmes to use was the challenge.  The three most recent ones are truly great, but, for me, Jeremy Brett is still the best match to Conan Doyle's work.  Feel free to disagree.