Rather than charging off into new directions, the focus of this book seems to be trying to fit in "morphic resonance/fields" within the context of evolutionary science, and, as such, spends most of its time framing elements of the latter, and then over-laying "morphic" elements to explain various particulars. Now, this is not to say that this isn't fascinating in places, but (again, for me) the book really dragged while waiting for "the good parts". Perhaps most interesting here was a look at how genetic sequencing should not have the data depth to be able to achieve what standard gene theory would have it do as far as replicating systems, and proposing a "field of habit" (much like Waddington's "Chreodes") that would guide development along established paths, something along the lines of how Roman carriages' wheel bases (by way of creating defined ruts in well-traveled roads) eventually determined railway gauges, which were a limiting factor in various parts of our space program.
If you're not familiar with Sheldrake's work, he's the "hundredth monkey" guy ... who suggested that once a novel behavior, achievement, or synthesis, has been actualized (in the case of the monkeys, it had to do with washing sand off of fruit, and when a sufficient number of monkeys in one region picked up this habit, it quickly spread to similar monkeys in geographically isolated areas), it becomes easier to repeat (another example is the synthesis of new forms of crystals in the lab, once a crystal has been successfully developed in one place, it becomes vastly easier to create elsewhere). Sheldrake popularized the concept of the "morphic field" which would carry the impression of these "forms" which would then be available to steer further similar situations towards similar ends. Of course, there is no hard evidence of how/where these fields might exist (and Sheldrake admits this), but he has reasonably convincing arguments that they have at least a fair likelihood of being there. For an example of "how this would work", think of the classic grade-school science experiment with a bar magnet, a sheet of paper, and iron filings. We can't see the lines of magnetic force from the magnet, until we sprinkle the filings on the paper above the magnet. Sheldrake would have it that Morphic Fields work similarly to drive behavior and evolution, even if we can't identify the "bar magnet" of their force.
Of course, Morphic Fields could go a long way to explaining the similar development of assorted marsupials related to the placental animals filling extremely similar niches elsewhere, as one example. Sheldrake also spends a lot of time looking at previous philosophical approaches to the issues at hand, and tries to fit in his theories within these contexts as well. Additionally, throughout the book he has suggested experiments that could be performed to test various aspects of the theory, as well as reporting on ones that could suggest its activity. One among these involved taking a well-loved Japanese nursery rhyme, along with two similarly-constructed rhymes, one that made sense, and one that was just random words. The one known to generations of Japanese children was best recalled by the mono-lingual American test subjects 62% half an hour after a session where all three were repeatedly recited (one would expect a 33% rate).
Anyway, I'm sure that other readers would likely find this of more interest than I did. It's got a lot of good stuff in it, but it's aim seems to be putting Sheldrake's theories into certain contexts, and in this effort a whole lot of (to me) less interesting stuff gets covered. The Presence of the Past does appear to still be in print, so you should be able to find it at your local brick-and-mortar book vendor, but Amazon has it at a third off and their new/used vendors have "new" copies for just a few bucks. If you're a "life sciences" fan this would likely be a much better read for you than it was for me!