What are some good books on calculus and on mathematical problem solving?

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Problem

What are some good books on calculus and on mathematical problem
solving?

[ Editor: problem statement reconstructed from the material, an
unattributed short reading list. ]

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CALCULUS

Calculus: A Genetic Approach  -Toeplitz
     An elementary and leisurely historical approach to calculus.

PROBLEM SOLVING

How To Solve It -Polya

Hungarian Problem Book I -(NML)

Hungarian Problem Book II -(NML)
   These are books of problems (with solutions) taken from famous high
   school mathematical contests that were held in Hungary around the
   turn of the century.

The Stanford Mathematics Problem Book -Polya and Kirkpatrick
   Another book of high school contest problems.

What is Calculus About? (don't remember author's name):
   I found this in the library in junior high school.  Within a few
   days, I was working my way through Thomas's classic college text.
   ``What is Calculus About?'' was like a bolt of lightning, sudden
   enlightenment, access to Nirvana.