I am one of those people who never got over their childhood dinosaur obsession. Yet in the past twenty years or so, I have regretted an increasing sense of diminishing control over the data set, which I have tended to attribute to the distractions of adulthood.

Two new books on dinosaurs have given me sweet relief. Darren Naish's The Great Dinosaur Discoveries and Scott Sampson's Dinosaur Odyssey approach the vast array of dinosaur varieties now known in novel ways, turning what is too often presented as a list into a way of thinking.

Traditional dinosaur books make a stab at this. They begin with a summary of the first dinosaur fossil discoveries in England. They cover the tasty feud between American paleontologists Charles Othniel Marsh and Edward Drinker Cope in the late 19th century, the two competing to name new species from hauls from out west and delighting in one another's mistakes. Finally comes the announcement of the "Dinosaur Renaissance" of the 1970s.

Traditionally, dinosaurs were depicted as sluggish creatures, dragging their tails, inclined to lounging in water, with a general "racial senescence" possibly causing their extinction. However, analyzing skeletons of a close relative of the Velociraptors famous from Jurassic Park, with their lithe bodies, large eyes, and razor-sharp second-toe claws perfect for eviscerating prey, paleontologist John Ostrom suspected dynamism. One look at the wiry, vicious mount of the skeleton of the creature in question, Deinonychus, at the Museum of Natural History in New York leaves us moderns to wonder how scientists could ever have supposed that dinosaurs were iguana-like sluggards.

Reinforcing Ostrom's analysis was how very similar the skeletons of these creatures are to those of birds—lively creatures with warmth generated from within, as opposed to reptiles' reliance upon the sun to warm their blood. A new generation of paleontologists developed a new conception of dinosaurs as fast-moving, warm-blooded creatures, standing erect on land, brightly colored and ready for action, and with birds as their direct descendants—such that technically, sparrows and penguins are dinosaurs.

This vision permeated popular culture and sparked an explosion in scientific work. Despite the plethora of children's books on dinosaurs that people like me devoured in the 1960s and '70s, since the '30s there had been little new research on the creatures, who were considered torpid evolutionary dead-ends.

Here, however, is where the issue of my own fears of senescence come in. A pleasant thing about those old books was that even in the ones covering all species known from more than a few bones, you dealt with perhaps 125 animals, falling into eight or nine major groupings. It was a nice little collection of "figurines" that a nerdy kid could easily commit to memory.

These days, that's a tougher proposition. A modern dinosaur book, after a quick historical survey, typically gets down to The List. Today, however, that means several hundred varieties—and as Naish mentions, 85 percent of the species of dinosaur known today were discovered in just the past twenty years. What was once a compact set subject to recitation, like The Presidents and Their Wives, has become an encyclopedia.

Naish's and Sampson's books both attempt to wrest a narrative for the layman from this newly daunting body of knowledge. Naish's is the first dinosaur book to take an angle it is surprising no one thought of before: to hang the entire presentation on a timeline format. Rather than restricting chronology to a prefatory appetizer and then bringing on The List, Naish presents dinosaurs in the order of their discovery right up to last year, highlighting what contribution the discoveries made to a developing science rather than simply describing them.

Sampson, meanwhile, situates dinosaurs within an ecological conception. Drawing broad but cautious conclusions from details of anatomy, physiology, preservation, and creative reconstruction, Sampson's academic bricklaying translated for laymen cannot be deemed, as one of his blurbers has it, "the best general-audience dinosaur book since the Dinosaur Renaissance began in the 1970s." It is, for one, too specialized for that honor, which arguably could go to Naish's book. Sampson's tome will communicate most effectively to readers who not only want more than the typical "Triceratops had horns above its eyes and lived in herds" museum tour but are ready for lessons in climatology, botany, and entomology in the context of evolutionary history.

Read together, Naish's and Sampson's new books give us a sense of the vast array of dinosaurs as keys to puzzles in a science proceeding ever forward. For example, back in the day, a dino fan knew a rather static fact: the meat-eating bipedal kinds of dinosaur (theropods) came in two types. Some were the big kind, like Tyrannosaurus Rex, and some were smaller, such as the poison-squirting Dilophosaurus in Jurassic Park. Early on, so the story went, one branch of theropods got big while the others stayed small, and The List was a matter of cataloguing a burgeoning list of Big Ones and Small Ones.