Professor Grünbaum's Gifford Lectures have not yet been published. That said, they will be included in the third volume of his collected works. The first volume was published in 2013, and the second and third are forthcoming. Here is the description of the first volume (with reference to the second and third) from the publisher's website:
Adolf Grünbaum is one of the giants of 20th century philosophy of science. This volume is the first of three collecting his most essential and highly influential work.
The essays collected in this first volume focus on three related areas. They discuss scientific rationality-the problem of what it takes for a theory to be called scientific, and ask whether it is plausible to draw a clear distinction between science and non-science as was famously proposed by Karl Popper. They delve into the debate between determinism and indeterminism, in both science and in the humanities. Grünbaum defends the position of the Humane Determinist, which then leads to a thorough criticism of the current theological approaches to ethics and morality-where Grünbaum defends an explicit Secular Humanism-as well as of prominent theistic interpretations of twentieth century physical cosmologies.
The second volume is devoted to Grünbaum's writings on the Philosophy of Physics and Space-Time, and the third to his lectures on the Philosophy of Psychology and Psychoanalysis, including his 1985 Gifford Lectures, which are to be published for the first time.