Maths and a hard chair
teaching
Serious reading of mathematics is best done sitting bolt upright in a hard chair at a desk. Pencil and paper are nearly indispensable; for there are always figures to be sketched and steps in the argument to be verified by calculation. (Savage 1972) (preface to first edition)
References
Savage, Leonard J. 1972. The Foundations of Statistics. Dover Publications, Inc.