Their adventures and escapades are told in long-ish, reasonably stand-alone chapters. Tommy is the dad of the family, and we get to know him, his wife and two children pretty well through the book.
‘Tales of Tommy Twitchnose’ is a great read-aloud for young primary-aged children. The length of the stories might put off a pre-schooler (although you could always read in stages) and the subject matter would probably lose the interest of an older child, but my 6-year-old twins enjoyed having these stories read to them.