The review deals with the chemistry concerning the processes of mild and selective oxidation of alkanes and cycloalkanes by using synthetic iron complexes as catalytic systems. These cover a number of coordinated species of iron ions including the so-called Gif systems up to the polydentated Que's models, aimed to mimic or emulate the non-haem enzymatic oxidation of alkanes. Special attention is paid to the mechanisms proposed by the various Authors and to the arguments set out for and against the free-radical interpretation to account for the activation of the C-H bonds. The schemes of the free-radical chemistry of Fenton reagents in the presence of organic substrates are quoted as a reference basis for the discussion.