Irvine wrote A Guide to the Good Life in 2009, and the book substantially predates and helped enable the contemporary Stoic revival. He approached the tradition as a philosopher of practical ethics looking for a working philosophy of life — testing the Stoic answers against contemporary alternatives (Buddhism, hedonism, consumerism) and concluding that the Stoic system was the most credible and most usable of the historical options on offer.
The book is plainly written, lightly footnoted, and organised around three problems: how to be happy, how to handle setbacks, and how to live in a society that does not share your values. Irvine's specific modifications to the inherited system are useful and modest. He prescribes daily negative visualisation — premeditation of adversity, repackaged for the reader who is meeting the practice for the first time — as the single most important Stoic exercise. He proposes a trichotomy of control in place of Epictetus's dichotomy: things over which we have complete control, things over which we have no control, and things over which we have some control (the outcome of a game, the impression we make in an interview). The dichotomy purists object; the practical benefit for new readers is real.
Where Irvine is weakest is in his treatment of the harder Stoic doctrines. Cosmopolitanism, the theology, the doctrine of fate, the preferred indifferents — these get less attention than the techniques. The book is, in effect, Stoicism as a self-help system, defended on the grounds that the harder parts are detachable. Stoics who want the system intact will disagree. Stoics who want a working practice tonight will find that Irvine has given them one.
He is the modern Stoic to recommend to someone whose first Stoic text he is being given. Then move them to Pigliucci, Robertson, and Hadot — in that order — as their interest deepens.