Transport Phenomena contains many instances of hidden messages and other word play.
For example, the first letters of each sentence of the Preface spell out "This book is dedicated to O. A. Hougen." while in the revised second edition, the first letters of each paragraph spell out "Welcome". The first letters of each paragraph in the Postface spell out "On Wisconsin".  In the first printing, in Fig. 9.L (p. 305) "Bird" is typeset safely outside the furnace wall.