Sheldrake has devoted much thought and speculation on trying to find reasons for some of life's more peculiar and spooky occurances, such as how dogs seem to know their owners are coming home, how separated siblings sometimes seem to experience symptoms of the other's illness despite living in a different continent, and how it takes bloody ages to try and get a protein to crystallise, but once one lab manages it, lots of others seem to be able to with ease. You know - basically 'things which make you go hmmmmmm...'
Science generally has no explanation for observations of such happenings, and indeed scientific wisdom would suggest there can be no causal reason for them and they are simply flukes and/or people seeing patterns which are not there. Sheldrake, however, has developed the concept of the "morphic field" in an attempt to "explain" them.
According to his 1981 book A New Science of Life, such a field would make it so that once a species has evolved, the next species to evolve would look something like it, apparently due to the universe having a memory as it is alive. Or something.
He has an entire section of his website dedicated to "Skeptics", that is, people critical of his ideas.