Until recently the drive to discover and utilize renewable feedstocks for the production of energy and for the manufacture of materials was exceptionally strong. Now, however, because of the realisation that nonrenewable (e.g. gas and oil) reserves are still superabundant, a different emphasis is appearing. This involves utilizing both nonrenewable and renewable feedstocks in an environmentally responsible manner. One important recent development involves the drive to utilize feedstocks, such as pyrolysis oil, microalgae and general bio-waste, like sawdust and other nonedible products from lignocellulose. Another is the aim to ensure that CO2 can be converted to fuels or useful materials, thereby diminishing its concentration in the atmosphere. This paper focuses on these themes; but it also addresses other important specific questions. Among these, the following are of particular interest: (i) How may catalytic cracking be made more environmentally acceptable? (ii) The emergence of single atom catalysts as means of effecting important chemical reactions.