Since I know of no (semi-)popular publications that deal especially with Paleocene mammals, I can only provide some recommendations for fossil mammals in general. The books below all aim at adult readers.
Benton, M. J. 1991: The rise of the mammals. Eagle Editions.
This should be the most recent semipopular overview of the history of mammals. Contains many nice drawings of extinct mammals and photographs of their fossils.
Savage, R. J. G. & Long, M. R. 1986: Mammal evolution. An illustrated guide. British Museum (Natural History).
Probably the most comprehensive non-technical book on fossil mammals that was published in the last two decades. Besides many excellent restorations, there are numerous line drawings of fossils, so it looks a little like a popular edition of the chapters on mammals in Carrol (1988).
Kurtén, B. 1971: The age of mammals. Columbia University Press, New York.
Although a little outdated, this books still gives a very good overview of mammal evolution in the Cenozoic, including a long chapter on the Paleocene. Drawings and plates are present, but the focus is clearly on the text.
Augustí, J. & Antón, M. 2002: Mammoths, Sabertooths, and Hominids. 65 Million Years of Mammalian Evolution in Europe. Columbia University Press.
A great summary of Cenozoic mammal evolution in Europe, richly illustrated in the style of "The Big Cats and Their Fossil Relatives". Although the text does not go into too much technical detail, it still aims at more serious students of the subject. The chapter on the Paleocene is up-to-date and quite detailed, and some of its unique restorations might soon appear on this site.
Flannery, T. 2001: The Eternal Frontier. An Ecological History of North America and Its Peoples. Atlantic Monthly Press, New York.
In a continuous flow, the author narrates how North America, its flora, fauna and finally its people changed from 65 million years ago to the 20th century. "The Eternal Frontier" is a vivid synthesis of results from different disciplines like geology, botany, zoology, anthropology and history. This is also the strength of the chapters on the K/T boundary and the Paleocene, although mammals are not treated in too much detail and there are some errors like calling Procerberus a hoofed mammal. Besides a few colour plates, there are hardly any illustrations.
Simpson, G. G. 1980: Splendid isolation, the curious history of South American mammals. Yale University Press, New Haven.
This book tells in remarkable detail how the South American mammal fauna changed over time. Although recent discoveries for the early Tertiary have changed some of the conclusions, looking for this classical work in your local library is still worth-while.
Schaal, S. & Ziegler, W. (editors) 1988: Messel. Ein Schaufenster in die Geschichte der Erde und des Lebens. Verlag W. Kramer, Frankfurt am Main. (English edition: Messel. An Insight into the History of Life and of the Earth.)
Koenigswald, W. et. al. 1998: Messel. Ein Pompeji der Paläontologie. Verlag Thorbecke, Sigmaringen.
Two more recent books on the famous Messel fauna from the Eocene of Germany. The first one discusses more in detail the groups of fossil animals found at Messel, the second one puts more emphasis on the visual presentation of the magnificient fossils.
Archer, M., Hand, S. & Godthelp, H. 1991: Riversleigh. The story of animals in ancient rainforests of Australia.
A richly illustrated book on late Cenozoic mammals and other vertebrates found in Queensland, Australia. The only direct link to early Tertiary mammals is a short reference to the Murgon fauna, which is probably early Eocene. Yet this book stimulates your imagination how the Australian mammal fauna might have looked like at earlier times ...
Cox, B. (editor) 1988: Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. Macmillan London Limited.
Although about fossil vertebrates in general, this book contains an extensive section on fossil mammals, with life restorations of many less widely known genera.
Kurtén, B. 1988: Before the indians. Columbia University Press.
A beautifully illustrated and very readable overview of North America's vertebrate fauna just before and during the Ice Age.
Williamson, T. E.1996: The Beginning of the Age of Mammals in the San Juan Basin, New Mexico: Biostratigraphy and Evolution of Paleocene Mammals of the Nacimiento Formation. New Mexico Museum of Natural History and Science, Bulletin 8, p. 1-140.
An up-to-date overview of early and middle Paleocene therian mammals from the famous San Juan Basin, as well as faunal lists for many other North American localities.
Rose, K. D. 1981: The Clarkforkian land-mammal age and mammalian faunal composition across the Paleocene-Eocene boundary. University of Michigan, Papers on Paleontology, v. 26, p. 1-197.
A good starting point for exploring the North American later Paleocene, even if the conclusions about the Paleocene/Eocene boundary are outdated. Contains many annotated faunal lists for middle and late Paleocene localities.
Archibald, J. D., Clemens, W. A., Gingerich, P. H., Krause, D. W., Lindsay, E. H. & Rose, K. D.: First North American land mammal ages of the Cenozoic Era; in Woodburne, M. O. (ed.): Cenozoic mammals of North America. Berkely, University of California Press, p. 24-76
The basis of the currently used biostratigraphic zonation for North American Paleocene mammals, with stratigraphic range charts and geographic occurrence data on genus level.
Savage, D. E. & Russell, D. E. 1983: Mammalian Paleofaunas of the World. New York, Addison-Wesley Publishing Company, 432 p.
A global overview of Cenozoic mammalian faunas. Includes a chapter that summarizes the fossil record for the Paleocene.
Russell, D. E. & Zhai, R.-J. 1987: The Paleogene of Asia: mammals and stratigraphy. Mémoires du Muséum National d'Histoire Naturelle, Série C, vol. 52.
A survey of Paleocene, Eocene and Oligocene mammalian faunas in Asia. Includes the most comprehensive synopsis of Paleocene mammals for this continent.
Janis, Ch. M., Scott, K. M. & Jacobs, L. L. 1998 (eds.): Evolution of Tertiary Mammals of North America. Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals. Cambrifge University Press.
The most up-to-date overview of North American Tertiary mammals. Morphological features, systematics, biology and evolution are discussed for each group. Occurrences are coded with a unified locality list. I'm looking forward to volume 2.
McKenna, M. C. & Bell, S. K. 1997: Classification of mammals. Above the Species Level. New York, Columbia University Press.
The current reference for the classification of recent and extinct mammals. Publication on the internet is planned by the American Museum of Natural History.
Carroll, R. L. 1988: Vertebrate paleontology and evolution. Freeman and Company.
Although this book covers all classes of vertebrates, mammals are treated extensively. All the major groups of mammals are introduced with their basic characteristics and fossil record.
Thenius, E. 1989: Zähne und Gebiß der Säugetiere. Handbook of Zoology, volume VIII, part 56. Walter de Gruyter.
An excellent survey of the highly diverse dentition of mammals. Even without knowledge of the German language you should get some benefit from the over 800 figures.