To celebrate Professor Robert Dewar's 65th birthday, a Symposium was held on 31 October2009 in Atlanta, Georgia, just before the 51st Annual Meeting of the Division of PlasmaPhysics of the American Physical Society. The Symposium was attended by many of Bob's colleagues, friends, postdoctoral colleagues and students (present and former). Boyd Blackwell, Anthony Cooper, Chris Hegna,Stuart Hudson, John Krommes, Alexander Pletzer, Ellen Zweibel, and I gave talks that covered various aspects of Bob'swide-ranging scholarship, and his leadership in the Australian and the US fusion program.At the Symposium, Bob gave an insightful talk, published in this issue as a paper withD Leykam. This paper makes available for the first time unpublished results from Bob'sM Sc Thesis on a general method for calculating the potential around a `dressed' test particlein an isotropic and collisionless plasma. The paper is interesting not only because it provides aglimpse of the type of elegant applied mathematics that we have come to associate with Bob, but also because he discusses some leitmotifsin his intellectual evolution since the time he was a graduate student at the University ofMelbourne and Princeton University. Through his early encounter with quantum field theory,Bob appreciated the power of Lagrangian and Hamiltonian formalisms, which he used withgreat effectiveness in nonlinear dynamics and plasma physics. A question that animates muchof his work is one that underlies the `dressed' particle problem: if one is given a Hamiltonianwith an unperturbed (or `bare') part and an interaction part, how is one to obtain a canonicaltransformation to `the oscillation centre' thatwould reduce the interaction part to an irreducibleresidual part while incorporating the rest in a renormalized zeroth-order Hamiltonian? Onesummer in Princeton, I worked with Bob on a possible variational formulation for this problem,and failed. I was daunted enough by my failure that I turned to MHD relaxation theory formy PhD thesis under Bob's supervision. It was a good decision because Bob showed mehow beautiful MHD theory can be, but he did not himself give up the problem of formulatingoptimal oscillation-centre transformations. He has a singular ability to hold difficult problemslike this in in his mind for many years until they crack open (or even if they do not!), a traitthat many of us find altogether admirable. The impact of such thinking on plasma turbulencetheory over the last four decades is described in the article by John Krommes in this issue.Stuart Hudson's article touches on some of the same themes in the pursuit of fully three-dimensional relaxed states in toroidal stellarators.Zensho Yoshida has contributed an interesting article on the interplay of Lagrangian andEulerian representations of collective motions in a fluid, a theme that appears in Bob's workin several contexts. Underlying much of Bob's work on Hamiltonian systems is his deepknowledge and appreciation of Lie perturbation theory, and the article by Steven Richardsonand John Finn, which discusses an example of symplectic integrators and their numericalimplementation, reflects that interest.It is impossible to do justice to all of Bob's contributions to theoretical plasma physicsin this short section. Bob's WKB theory of ballooning modes in three-dimensional toroidalsystems (with Alan Glasser) is a classic paper that was in some ways years ahead of its time,especially in its exploration of the deep connections between KAM theory and the nature ofthe spectrum. In later work, he developed these ideas further by establishing connections withthe phenomenon of Anderson localization in condensed matter physics. His papers on thesubject of ballooning modes are gems of the plasma physics literature, and are unsurpassed intheir mathematical elegance, insight, and their development of broad connections with otherfields of theoretical physics. Some of this was covered in the talks at the Symposium. The paper by David Barmaz and coworkers published in this issue discusses the problem diamagnetic stabilization of ballooning instabilities in stellarators.It is not surprising that Bob's work on ballooning modes shows an accomplished master ofWKB theory at work, for it is the culmination of a process that began many years earlier. Hisinvolvement in applications of WKB theory to problems involving instability and turbulencebegan in 1970, when he was a graduate student. At this time he wrote a very influential paper,discussed at the Symposium, on the interaction between hydromagnetic waves and a timedependentinhomogeneous medium. This paper is widely cited, especially in the astrophysicaland space plasma literature, for it gives a rigorous method of evaluating the effects of lowfrequencyhydromagnetic fluctuations on a slowly varying background medium. The methodhas found use in problems as diverse as the self-sustainment of molecular clouds, the heatingand acceleration of the solar wind, and the effect of cosmic rays on the interplanetary medium.Attentive readers will note that Bob has been drafted as a co-author and participant inabout half of the publications in this issue. This is a reflection of Bob's continued and tirelessinvolvement in a wide spectrum of research problems that have their genesis in his fundamentalcontributions to plasma physics, as well as the eagerness with which we all welcome hisinvolvement in our own projects. We hope to have this continue for many years to come.