Mostly Mice is a comic book featuring original characters drawn by the author. The book is thirty-one pages long and is divided into two sections. The first section is a satirical time line showing mice from the age of dinosaurs to a possible future. The second section depicts "musical mice"--characters playing various musical instruments. Each illustration is accompanied by a caption featuring word play such as puns and alliteration. Children between the ages of ten and twelve may find the humor amusing and entertaining. They may also find the drawings appealing.